My Vampire Older Sister and Zombie Little Sister:Volume5

Illustrations

• 

  Cover

• 

  Magatsu Taori

• 

  Himatsuri Asami

• 

  Himatsuri Minaki

Chapter 0

[Self Record] Basic Information [Leviathan's Report]

Pride:

• Lucifer, Azazel, etc.

Wrath:

• Satan, Amon, etc.

Envy:

• Beelzebub, Leviathan, etc.

Gluttony:

• Beelzebub, Molech, etc.

Greed:

• Behemoth, Mammon, etc.

Sloth:

• Belphegor, Lilith, Astaroth, etc.

Lust:

• Belphegor, Asmodeus, etc.

...There are too many of them. Some of them are in multiple slots. And alternate names like Satan and Lucifer just make it more confusing. There are multiple candidates because the situation changes depending which version of European theology you are looking at, but the dignity of the title "Demon Lord" fades a bit when their numbers reach the double digits. Then again, this is a theory put together by theologians to conquer the fear of demons, so that may be the right way of going about it.

Chapter 0

"Huhh? Taori-san, did you take someone in again? Well, not that I can complain when I'm a freeloader too."

I was a mess.

I had been thoroughly beaten.

But not by anyone out there in the world. By my own ugliness.

I still felt depressed as a woman in a white dress and cardigan, who had once been my mother, led me to a high-rise apartment building I had never seen before. Instead of blending into the similar buildings of a residential district, it stood out from the coastal shopping district and would have made a good landmark. As soon as we stepped inside one apartment, we were greeted by a confused voice.

"You really do like this kind of thing, Taori-san. Have you already forgotten how mad the landlord was when you brought back that big dog even though this place doesn't allow pets?"

It was a flashy blonde girl in a champagne-red dress who spoke to my mom. I didn't know what to call her hairstyle, but the silhouette of her head looked like it was part of a revolutionary new trend in flower arrangement. I had never seen the real thing, but she looked like the cabaret girls I had seen in dramas. She had a lot of accessories on her hands and around her neck. I doubted she was in high school, but she looked a little young to be in college. Her flashy appearance may have been leading me astray, but I had difficulty grasping her age or figuring out how formal to act around her.

My mom, Magatsu Taori, silently nodded.

"You can tell?"

"Well, yeah. He's in some kind of trouble like me, right? Besides, do you have any idea how late it is? You were only just freed, so I know you aren't about to bring a young boy home with you for no real reason. That would be a waste."

The cabaret girl waved her hand dismissively before continuing.

"I'm Himatsuri Asami. Nice to meet you, runaway boy."

"Oh, um, uh."

Who was she?

My mom had supposedly been trapped below an abandoned hospital for more than three years, so had these two recently met and really hit it off?

"What? You aren't going to introduce yourself?"

"I'm...Amatsu Satori."

"Amatsu?"

This Himatsuri person curiously repeated my family name. She was clearly wrinkling her brow. She apparently knew my mom well enough to be familiar with her family situation.

Which would include that she had returned to her maiden name after the divorce.

"Oh, well, this is quite something... T-Taori-san? Did you do something rash!?"

"I didn't take him away from his home. I just happened across him looking like this, so I was worried..."

"That excuse will only work with your friends! Oh, honestly. I'll contact my family lawyer, so you just be honest about everything that happened. I'll get this straightened out, but don't you know how messy child custody issues can be!?"

Himatsuri-san began mussing up her own impressive blonde hair and then called someone up on her smartphone. Despite her flashy appearance, she may have been the sympathetic type who would help anyone out with their problems.

And a family lawyer? Did that mean she was rich? If she was living here, she must not have had her own cook or driver, though.

My mom watched the cabaret girl(?) walk out onto the balcony with the phone and then she laughed and turned toward me.

"Don't worry. If Asami-chan says she'll straighten this out, then she will, so you don't have anything to worry about."

"Um..."

"You don't have to tell me everything. Just stay here for as long as you need to and head home once you think you can."

That was extraordinary.

But that was why I couldn't help but wonder why she would go this far.

And she must have sensed the doubt in my face because she relaxed her shoulders and whispered to me.

"It's best if you don't understand. Especially at your age."

Of the few rooms, she showed me to the living room and reached for the TV remote.

"Defeat 100 comedians with your trademark gag? Easy! I've made it 20 years with one impression! Dwah hah hah!!"

"It has been revealed that the military was involved in the largescale infrastructure damage done by the slime Archenemies in Las Vegas, and it is looking possible that the entirety of Congress will resign..."

"Marine Biology Quiz! This week's theme is sharks! They get a bad rap, but most of them aren't all that violent."

She flipped through a few channels, but she probably wasn't looking for anything in particular. She was just trying to distract me, so she was focused on finding something calming to watch.

"Given the time, you can think of it as a late night snack, but do you want me to fix you some pancakes, Satori-chan?"

"?"

"You liked them, didn't you? With ice cream on top? Assuming Asami-chan didn't eat it all, there should be some vanilla left in the freezer."

At first, I had no idea what she was talking about, but she wasn't remembering wrong. I vaguely recalled eating that a lot when I was little.

Was our family still frozen in time in her memories? If so, that was sad. She had not made a new family or started on a new life. And it had happened because I hadn't gone with her after the divorce.

She slowly removed her cardigan and called out to the balcony.

"Asami-chan, what did you do with the bath?"

"Right, right. So make it top priority! ...Yes? I left the bathwater in the tub. I thought you would want to take a bath when you got back."

"You heard her. I'll reheat the water, so take a bath. You're exhausted, aren't you?"

"Eh? But...?"

"The basics of life matter. When there's a weight on your mind, satisfying your body's needs is the best first step. Or do you want to take a bath with your mom like old times?"

"Okay, okay, let's not make this more complicated than it already is!! I can hear everything you're saying!!" Himatsuri-san stormed in from the balcony and then pointed straight at me. "There's only one rule here. You can cause Taori-san all the trouble you want, I'm in no place to criticize you for that. But make her cry and I'll hit you, no matter how much she tries to stop me. Understand?"

Since she wrapped her expensive-looking watch around her palm instead of forming a fist, she must have been used to getting into fights. Was she planning to scratch me with the watch's face? When I nodded several times, she smiled. It looked like she had accepted me as one of them.

"That's fine then. I'll pick a fight with the world too."

I was then pushed on over to the changing room. At this rate, I started to think I really would be served pancakes with vanilla ice cream on top.

Once alone in the changing room, I looked in the mirror and pulled out my smartphone.

"Maxwell."

"Sure. You have 34 missed calls, 20 emails, and 58 text messages. How will you respond?"

"Sorry... Can you just ignore those for now?"

"That is a disappointingly pathetic response, but I suppose you are not hopelessly pathetic as you did not ask me to erase them."

I was well aware how horrible and lame I was being here.

Las Vegas had been taken over by the slime Archenemies we called gels. It had been destroyed by the air force bombing meant to suppress the gels. I had saved the people swallowed by the gels, but that was all. Behind the scenes, it had all been connected to the tickets for an ark known as Absolute Noah. My stepmom, Amatsu Yurina, had given tickets out to the people who had been selected by the machines because they had top priority “on paper” and she had used that to wipe them all out so they would not take up the spots needed for the people who truly deserved to survive. She had intentionally caused a disaster, given those black-hearted people false arks, and made sure they could not hope for anything more than that.

And?

So what?

What had I done when I learned the truth? I had thoroughly criticized my stepmom, but I had failed to get her to say she wouldn’t do it again. I couldn’t even get her to apologize.

No, I had known from the beginning that nothing I said would draw out the words I wanted to hear.

I had known that, but I had still hurt my family.

Issues of justice and stopping that grand plan had been second in my mind. All I had done was throw my frustrations at her. And then I had run off, made sure she couldn’t find me, and then made myself a burden on my biological mother who I had supposedly parted ways with already.

…Is this the kind of person I wanted to be?

What kind of person had I dreamed of being in those crayon drawings on construction paper when I was little?

“I have already made my judgment of you, user. You are pathetic but not hopelessly so.”

“What’s the difference?”

“At the time, a few different options were available to you: get into a fight with Madam Amatsu Yurina and drive her out of the house, leave the house yourself, or pretend it had not happened.”

Maxwell spoke through a series of social media speech bubbles.

“You could not keep quiet about this unreasonable world, but you also could not take away a family member’s home. So you left yourself. …That means you are quite fragile, but with a strong sense of justice and kindness. Thus you are not as hopeless as those who let their sense of justice narrow their vision to the point of swinging their fist in their own home.”

Did that mean I was walking the same path as my mom who had left our home after the arguments with my dad progressed too far?

“As a result, you alone have lost everything. Even though other options were available, such as turning your back on justice and laughing, or wielding your justice to threaten her. …So you should be proud of your decision. I am more than willing to support my pathetic user in this.”

“Is that so?”

I finally felt like I could see a slight smile on my haggard face in the mirror. A bit of flattery could really change your outlook on the world. That seemed pathetic, but I couldn’t just sit around.

“Maxwell. Send an email to Ayumi, Erika, and the Class Rep’s phones. Tell them I’ve just run away from home for a bit so they don’t need to worry.”

“Warning: I believe anyone who reads that will see it as something you were forced to write after being caught up in some kind of trouble.”

“That’s why I’m telling you to do it instead of me. They’ll be relieved to know my inspector is with me.”

“…I am most concerned about your monstrous sisters’ jealousy. It makes me feel like I have been caught up in an argument over what one thing you would bring with you to a desert island.”

I placed a towel over the smartphone on the washing machine, stripped off my clothes, and walked to the bath. The tub seemed larger than at home. Based on the control panel, it seemed to be an IoT appliance. It was apparently connected to the internet so it could heat the water according to the schedule on your phone. …But that seemed dangerous. Couldn’t a cyber attack start a fire or give you carbon monoxide poisoning? I thought about having Maxwell check it over for vulnerabilities later. Or would a white hacker like Anastasia enjoy doing that? It was probably best to ask the expert. And she was bound to do it if I presented it to her as a competition with Maxwell.

I used a washtub to scoop up some bathwater and washed away my sweat as I thought.

Whatever I was doing, it had to start tomorrow.

I had no idea how to solve this problem, but I couldn’t just leave it like this. The Calamity would supposedly destroy the population of the earth and Absolute Noah was the ark meant to survive it. I couldn’t avert my gaze from that.

With that in mind, I entered the tub feet first.

And as soon as I did…

I fell.

Where to? Into the bathwater filling it, of course.

I instantly sank in deeper than my head. I couldn’t breathe, intense pain shot through my eyes, and the heat of the water seemed to reach deep inside my head. I had no idea what had happened. I initially thought I had stepped on the soap and flipped over, but that wasn’t it. I was clearly still upright as I sank. …So was there no bottom!? It was like I had been thrown into a deep pool!

“Cough, cough!! Cough!?”

When I flailed my arms and legs around, I was clearly able to swim. Like I was trying to reach the top of an old well, I swam up in search of air. I finally parted the surface of the bathwater and filled my lungs with air, but the abnormal situation was not over yet.

“Wha-…?”

The bottom of the tub was back to normal. I could feel the smooth plastic supporting my butt.

But the room was dark and had no power. I could only observe my surroundings thanks to the bathwater.

It was bizarre.

The water was glowing with a sticky blue light, like it was glow-in-the-dark paint. The pale light came from both the water in the tub and the drops on the tiled walls. The mirror on the washing area’s wall had some kind of strange pattern drawn on it.

It suddenly hit me that this light was a lot like the ocean covered in sea sparkle I had seen in a documentary.

“What the hell is this?”

I crawled out of the tub and found my wet body was glowing the same color. It was more embarrassing than creepy. I dried myself off with a towel and then returned to the changing room.

I could hear large raindrops pounding on the wall.

…? That sounds like a typhoon. But it was such a clear starry sky outside…

“Maxwell. What is going on, Maxwell?”

I threw back on my clothes and reached for the smartphone covered in the towel on the washing machine.

But there was no response. No matter how much I tried, it would not connect to Maxwell. It had no signal anymore, making it entirely useless.

So was this not just a power outage or tripped breaker?

“…”

I thought for a bit and then realized something.

Something was written on the mirror in front of the sink. But it didn’t look like a text made up of meaningful characters.

Come to think of it…

I opened the door to the bath again. Sure enough, the same pattern was on the washing area’s mirror.

What was this?

I returned to the changing room and moved my face in close to the mirror. A few lines were intersecting. Were those supposed to be three-way and four-way intersections? It looked like a crude, hand-drawn map and one corner of an intersection had an arrow pointing to it.

Something changed as I watched it. As if the water on the mirror was dripping down, more blue glow-in-the-dark light was added.

“today’s exit”

That was all.

What was this? Had it happened on its own? I checked the bath and found the same writing on the mirror there. That was ridiculous. So was it not just a coincidence? Was there really writing here?

It felt like I had been thrown inside a simulator or a dream.

Ever since I had so unnaturally fallen into the tub, something had gone wrong with the world.

“Mom. Yes, mom.”

She would know something. …Wouldn’t she?

Either way, I didn’t have to worry over this alone. With that in mind, I threw open the door from the changing room to the living room.

Just then, a bunch of night rain slapped me in the face.

There was no room there.

It had been torn away like the aftermath of an aerial bombing in a war movie, so I simply saw a stormy night in front of me.

“Wha-…ah…?”

It made no sense.

What was I even looking at?

“Mom! Himatsuri-san!?”

I knew yelling was useless, but I still desperately hoped I would hear a voice in return.

How many floors up was this?

How had an entire room – no, an entire chunk of a high-rise apartment building – been torn away like this?

I could see my hometown of Kukyou City through the stormy rain and winds, but it wasn’t the city I knew. The dark scene was filled with a blue glow. This wasn’t just your average increase in water level. This flooding was easily as tall as a school. I couldn’t tell where the roads began and ended and I could only see the taller buildings sticking up from the dark water.

What had happened to my mom and Himatsuri-san?

And what about the others in the city? Like Ayumi, Erika…dad, and my stepmom!? Or the Class Rep next door!?

“Max-…no, that doesn’t work!”

I had never thought I would feel so forlorn just because my smartphone had lost its connection. I couldn’t share this absurd situation with anyone and I had to carry it alone. I just wanted to call someone I knew to know they were all right.

“A phone…”

As my mind nearly strayed from reality, this one desire kept it grounded.

“That’s right. I need to find a working phone.”

One corner of my mind rejected that idea with cruel rationality. What good was finding a home phone? A really old phone would be one thing, but modern multi-purpose phones needed more than just the phone line to power them. Everything was dark, and if that meant a blackout, I wouldn’t be able to use the phone. So there was no point in finding one.

But most of my mind refused to be so rational. It wanted to find a phone so badly.

The living room was almost entirely missing, so only a wall and a bit of floor remained. It would be suicide to walk along that 10cm surface during a storm and with only the wall to hold onto. I knew that, but there was a phone right over there. I could see that normal device there.

So I started to take the first step.

But I never completed it.

Why?

Because of the giant shark.

A shark rivaling a submarine in size broke the roiling water’s surface.

“Uuh.”

That snapped me back into reality.

The most insane sight yet reminded me of the very real possibility of death.

“Waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhhhhhh!?”

I had no idea how many floors up the water had risen, but the shark that leaped out of it had to be more than 30m long. It used all of its muscles to make the jump. I almost stared spellbound at the dark tunnel that was its maw, but then I pathetically fell backwards.

I fell onto the wet changing room’s floor.

And the elegant arc of the shark’s jump took it directly above me. It was like a head-on collision with a semi-truck pulling a large container. With a sound far louder than the storm or lightning strikes, the surviving boxy shape of the changing room was torn to pieces and swept away into the storm. The walls and ceiling were smashed up in no time. That thing didn’t even worry about the building walls. In hindsight, I realized the edges of the living room’s surviving wall and floor had been terribly jagged.

Was that it?

Had that thing done all this?

“…”

I didn’t have time to think about it. If it could destroy walls and ceilings when it attacked, there was no point in holing up in any kind of shelter. It knew I was here. If the next attack broke through the wall, I would have my entire body eaten and it would be game over. It could even tear down the entire apartment building.

“Wah!!”

Still in my clothes, I ran from the broken changing room to the bath. There was a window on the wall bordering the tub. I threw open that window and looked straight down.

The height made my vision waver.

But then I heard an incredible destructive sound directly behind me. In fact, I felt the heavy sensation of something stabbing into my back.

Was it one of the shark’s teeth? No.

I would have been bitten right through had it been that.

It was probably a piece of the wall that had broken off during the second attack on the changing room.

But that didn’t matter.

“Gh…ph…?”

I had trouble breathing and I lost my balance like I had been shoved from behind while standing on the edge of a cliff.

The open window was right there.

I suddenly remembered that this was the 8th floor.

At the same time, I was thrown out into the blowing wind of the stormy night.

I must have screamed something, but I don’t remember what.

I helplessly fell about three floors and was dazed by a powerful blow to the face.

Not the ground, though. That would have killed me instantly.

“Bwah!!”

When I got my soaked face above the salty-smelling water, I found what I expected. I had fallen into the sticky blue glow of the water flooding the city. I struggled against the powerful current and somehow managed to grab onto a roadside tree that was almost entirely submerged. It had to be about 4 or 5 stories tall.

But the water was that shark’s home ground.

I would be killed if I stayed here. Wasn’t there anywhere I could go to get inside? A balcony or an emergency staircase!?

I felt a chill on my spine as I looked around.

Then I saw something.

Every last one of the building windows above the water level had the exact same pattern on them, like a wall covered in identical posters. It was drawn out by the same blue glow I was drowning in. No, it wasn’t just a pattern. It was a map. It was a crude map without landmarks that looked like a kid might have drawn it. It had three-way and four-way intersections and one corner of a four-way one had an arrow pointing to it. And what looked like letters of the alphabet provided the one and only label: today’s exit.

“What am I supposed to do…?”

It took me a while since everyone relied on map apps these days, but I realized I did recognize that map.

I couldn’t see the roads or traffic lights with this flooding, but it was near my mom’s apartment. It was at the corner of a four-way intersection. I looked around and did indeed see something there. While everything else wetly glowed with a blue glow-in-the-dark light, this one spot shined with the light of a red-hot metal.

Was it…a door?

It was on a bowling alley. A strange metal door was directly attached to the wall without bordering anything else. It was probably meant for use with a firetruck’s ladder, but with the flooding, it looked like I could reach it if I swam directly to it.

And I didn’t have time to spare.

The powerful current didn’t give me time to think. As soon as my fingers were torn from the top of the nearly-submerged tree, I was swept away. Luckily, I was taken toward the orange glow.

I sensed a great pressure behind me.

That gigantic shark had found me. I could clearly tell that, but I couldn’t bring myself to look back. I hadn’t checked, but I could tell all too well just how accurately it was swimming toward me in this current. I was too afraid to just let the current take me, so I began an awkward crawl by mimicking what I had seen in the past.

What was this about?

What did that door mean?

I didn’t know, but I couldn’t stay in the water. I swam and swam and swam until I reached the metal door attached to the smooth bowling alley wall. I grabbed the knob, opened the door, and climbed in like I was a seal in an aquarium.

Just then, the entire broken city vanished like it had all been an illusion.

“…Eh?”

The pleasant sound I heard was probably someone in the alley getting a strike while playing late into the night.

I looked back and saw no blowing rain, no flooded city, no blue light…and no giant shark. I only saw the stillness of the night and the fact that this was definitely five stories up. With no water below, it was all over for me if I fell.

I stuck my head out through the metal door on the wall and saw my mom’s apartment building. It was not even 100 meters away. And it had of course not been destroyed.

What had all that been?

…If it had been a dream, then why wasn’t I collapsed in the changing room or bath?

I had definitely changed locations and I was soaking wet, although not glowing blue.

“Ow.”

And I felt a dull pain in my back. A piece of broken wall had hit me when that shark destroyed the changing room.

If that wound remained…

Would I have lost my life if I had died in that shark attack?

I couldn’t explain my presence in the bowling alley without having paid, so I descended the emergency stairs and made sure no employees saw me as I left. Then I returned to my mom’s apartment.

That had not just been a dream.

It felt like there were two worlds and I had passed between them for some reason.

“Was it the bathwater…no, just water in general?”

I made sure to avoid the puddle below a streetlight as I said that.

That was how it had started. I had gotten into the tub, but found it too deep to stand and nearly drowned. Then as soon as I had gotten my head above the water, everything had changed.

It was like diving into the moon floating in a lake at night.

How unrealistic could you be?

Should I just laugh it off like that? I had been inexplicably moved from the bath, I was soaking wet even though it wasn’t raining, and I had a dull pain in my back, but should I still write it off as me “imagining things”?

Since this was a shopping district, the first three floors of the high-rise apartment building were made into a small shopping mall. The first floor bordering the road was lit up especially bright since it contained a burger shop and a convenience store. The night-shift worker looked bored behind the register. I only mention that because this peaceful scene made it hard to believe a great torrent of water had flowed through here just a bit ago.

The parking lot was underground and used turntables and elevators. The entrance for residents was also in a more out-of-the-way location. That entrance used a simple autolock, but when I typed in the room number, it connected me to my mom.

“Eh? Satori-chan, how did you get outside?”

She was confused and she must have gone to check in the changing room and bath. After that, she unlocked the front entrance for me.

It seemed I had not just been sleepwalking and invented some convenient memories to explain it.

If I had walked through the bath, the changing room, and the living room to reach the front door, my mom or Himatsuri-san would have seen me. But there was no other way to leave that 8th-floor bath. …And yet here I was walking around outside.

Something wasn’t right.

I was caught up in something.

But what was it? What did that giant shark and flooded city mean?

The elevator arrived before I could find an answer.

Surprisingly, Himatsuri-san was riding it.

She clenched her fist and winked.

“Make Taori-san cry and I’ll hit you. I explained that rule, didn’t I?”

“Sorry…”

“Well, you’re fine for now. So why are you so wet? And you smell salty. Is there a fishing spot around here? This is along the coast, but surely you weren’t out on the beach or embankment.”

She had apparently come down to meet me. She did not get off the elevator and must have planned to make a U-turn right back up.

The sea smell must have been strong in the enclosed space.

But then I noticed the floral scent of shampoo or conditioner coming from Himatsuri-san as she turned her back to look at the floor counter. She had likely used a dryer on her hair before preparing that hairstyle, but the skin of her visible nape was somewhat flushed.

…Had she taken a shower?

But when my mom had asked about the bath, she had said she “left” the bathwater in the tub. That sounded like she had already taken a bath before my mom got back.

Not that it really mattered.

The problem facing me was more important, so I muttered to myself.

“Sigh. What was with that giant shark?”

“Sigh. What was with that giant shark?”

Hm?

Himatsuri-san and I both frowned and then exchanged a glance.

Why had our voices harmonized there?

Did that mean she knew about the giant shark?

She looked like she was wondering the same thing and my expression had to have been the same.

“You mean…”

“…You too?”

Our surprised comments were followed by a soft electronic tone. The elevator had reached the destination floor and the doors slid open.

[Self Record] About Sharks [Leviathan’s Report]

The largest of the fish.

The fierce species are most well-known, but the majority of them only eat small fish or plankton and the so-called “man-eating” varieties are extremely rare.

Setting aside their actual classifications and behaviors, the general public thinks of the great white when it comes to predators and the sturgeon when it comes to prey.

Ironically, this entirely changes if you include marine mammals as well.

The violent great white shark cannot match the size of a whale or the ferocity of an orca.

Thus, the shark is the symbol of the strongest within a limited environment. For example, the king of a ring in which everyone is divided into different weight classifications cannot win in a no-rules street fight.

Sharks cannot defeat mammals.

Thus it may be envy that leads them to so persistently target humans.

Chapter 1

Part 1

My smartphone was in the changing room where I had left it. And I could speak with Maxwell just fine.

"The law of conservation of mass has been broken."

"?"

"User, your clothes are folded up right here, so what is that you are wearing? And what is that smartphone in your hand? Not only is the SIM registration number identical, but the saliva spray, finger oils, and other bio-traces match as well. This will not solve the mystery, but I recommend removing one of the SIMs to avoid a conflict."

"...You're kidding, right?"

I compared the two identical smartphones.

This might seem insignificant compared to the submarine-sized man-eating shark or the blue water flooding the city, but I felt goose bumps silently covering my skin when I realized I had objective and undeniable proof that nightmarish experience had happened.

This seemed bad.

I probably needed to defend myself.

In that psychedelic world, all the mirrors and windows had said "today's exit". Today's? Why include that? Why wasn't "exit" enough? Didn't that mean this would happen tomorrow and the day after that as well!?

"...Maxwell."

"Sure."

"There's something I want you to research."

That something was of course the giant shark.

I thought about it all while facing myself in the changing room mirror.

Himatsuri Asami had experienced the same thing I did. That meant she had survived being pursued by that giant shark in that flooded city.

And the "today's exit" label suggested this had not started today. I needed to assume this had been happening for a while and I had only just been made a part of it.

That meant there might be more people having similar experiences. If there were enough of them, there could even be rumors about it online.

"Laugh and call it absurd if you like, but please follow my instructions first. Start by searching for the following terms: giant shark Archenemy, being chased by a shark in a glowing ocean, today's exit, and blue water with a glowing door. Show me a list of sites with a strong connection between those terms."

"I am not capable of spontaneous laughter. Beginning search."

I wasn't immediately sure what to do about my clothes, but I couldn't hang around my mom's apartment smelling like seawater. And if what Maxwell said was correct, then the ones on top of the washing machine were the real ones and the ones I was wearing were the physical evidence of the mysterious phenomenon.

There was no real reason for it, but I removed the one set and put on the dry set.

"User, is there any reason to cover the lens every single time?"

"It's basic etiquette. I'm not too fond of people who bring their phones in the bath or bathroom."

"But doesn't your bath-loving Class Rep-..."

"Don't say it!! Do you have any idea how much self-control it takes to not abuse your abilities there!?"

I grabbed the smartphone again.

"So how's the search going?"

"I have not discovered a shark Archenemy. The closest result would be Forneus, one of Solomon's 72 Demons."

"Is it more than 30 meters long and can it knock over buildings?"

"Very few sites describe any details of its physical data, but that does not seem to match. Although its basic specs may be quite high if it is named alongside Solomon. It seems to be a specialist in language, learning, and the arts and it has the ability to reform one's enemies, but that suggests it does not specialize in direct violence."

"Hm. Man-eating sharks are always depicted as vicious monsters these days, so that's surprising."

"Also, the phrase 'chased by a shark' had a few hits on urban legend message boards. And the IP addresses suggest they are from people in or near Kukyou City."

"Give me a summary of what they're saying."

"I must warn you in advance: the majority of current internet lore is invented by freelance writers. They write a book on the very rumors they spread in order to look well-informed, so I suggest you place a strong mental filter over the reliability of this information."

It was a lot like spreading rumors of the Kuchisake Onna to increase sales of pomade or bekko ame. The world was a cruel place, but I needed to rely on anything I could. ...Besides, I knew for a fact it was "real" this time. Even if it had started with a freelance writer's story, they probably had some secret related to this shark.

Once Maxwell summed up the information found on several sites, message boards, and social media posts, the man-eating shark rumor was as follows:

• People of this world are dragged into the water's surface and thrown into a glowing ocean. (Various names for this glowing ocean exist: Sea Firefly, Blue Hell, Sea Sparkle, Lord's Ocean, etc. Presumably because so many people have told the story.) It is unknown why any particular person is chosen. Any water's surface is a threat if it is large enough for your body to pass through. Also, any clothing or tools in your possession remain with you, so it is best to be prepared in advance.

• Once someone has been dragged into that world, it will continue to happen. It seems to only happen once a day, so if your return from that glowing ocean, you will not be dragged there again until the following day.

• Once dragged there, you will be chased through a flooded city by a giant shark measuring more than 30 meters long.

• In the glowing ocean, anything that functions as a mirror will display a map with the exit door labeled with the words "today's exit". The exit's location changes each time, and there is no known pattern. It seems new doors are not created, so an existing door is designated the exit.

• It can be assumed circumstances could line up so the distance to or position of the door makes reaching it impossible. There is no guaranteed method of victory. The stories are only from the survivors who just so happened to be near the door and have a simple path to it.

• Any injuries received in the glowing ocean remain once you return to the real world. So it can be assumed death there means death in reality. It is unknown what happens to people who fail to pass through the door and are killed. Are they returned to reality or do they go missing?

• Once someone has been dragged there, they are forced to continue the challenge again and again. The only options for survival are escaping the glowing ocean or defeating the giant shark.

"...Please tell me this is a joke."

Urban legends sometimes had no avenue of escape for those involved. People spread them because they found it amusing when it was not happening to them.

But weren't the conditions here a little too harsh!?

"It keeps happening over and over, it's all at the mercy of the giant shark that we don't know how to defeat, and the randomized exit location could lead to an impossible setup? That's like being forced to play Russian roulette over and over. You might get lucky and survive for one day, but your luck isn't going to last forever. Isn't that how statistics work!?"

I just had to think back to my own experience.

What if the orange glowing door had been another 10 meters away? I would have been bitten by the giant shark and dragged to the bottom.

"No. Calm down, user. These are no more than internet rumors which are likely fabricated lies. There is no guarantee the conditions listed here match the actual phenomenon."

"Oh, right. Does it look like a freelance writer started it?"

"Following the timestamps of the posts reveals that it began about a month ago while the Bright Cross was still active. But the originator does not really matter."

"...?"

"If a writer gets involved in internet lore, it is to write an article on it. Even if there is an actual mysterious phenomenon behind it, that phenomenon may not be sufficiently interesting for an article, so their job is to rewrite it in an interesting fashion and spread it like that."

"You mean...it's possible a lot of this is embellishments added to the factual story told by the originator?"

"Sure. An incredible phenomenon such as this would make for quite a scoop. If a writer had investigated it on their own, they would write a paid article about it, not an unpaid post. It is much more likely that they were altering it to something profitable without knowing what they were talking about."

Then what was I supposed to do?

I hadn't really wanted to reject the online information.

I just wanted confirmation.

If yes, then yes. If no, then no. If I knew whether it was true or not, I could use that as a starting point, but this just left me unsure. I had no idea what I was supposed to do if I was to survive.

Where was I supposed to start investigating? Sitting around was not going to improve my situation. I didn't even know when I would be dragged back into that variation on Russian roulette where I was chased by a giant shark through a watery world that seemed to exist solely to kill people!!

"If I may be so bold, I would strongly suggest you solidify what footing you do have," said Maxwell.

"What does that mean?"

"Sure. You should check to see if your experience really matches that of Himatsuri Asami. And if wounds really do remain, you should probably search past newspaper articles for information on patients or corpses with unnatural wounds seemingly caused by shark teeth."

That was right.

People suddenly disappearing from the bath or falling into a roadside puddle like it was a pitfall might get written off as nonsense.

But it would be big news if a corpse seemingly mutilated by shark bites turned up in a small, locked apartment that did not even border the ocean. As strange as it was, there would still have to be records of it. And those official records would be maintained much more strictly than some internet lore from an unknown source.

...We would run into trouble if the dead were left in that glowing hell and were treated as missing people back in reality, but I didn't need to fear failure before I even made the attempt. I had to try everything I could.

"You should probably also see if anyone you know has experienced anything similar. For example, Miss Ayumi and Miss Erika."

"Oh, right! What about everyone else!?"

The flooded city was gone. It was now a still night without a single raindrop. But I could still feel the fear I felt when I saw the city engulfed in dark water. If I felt that way, so would everyone else. With the water that high, two-story houses like mine or the Class Rep's would be entirely submerged.

This could mean the deaths of those people closest to me.

It was only a "what if" at the moment, but it was enough to scare me.

I used a finger to scroll through my smartphone's address book. I was unsure who from my family to contact, but I ended up choosing my stepmom. ...If I avoided her now, I had a feeling I would never be able to shake the strained atmosphere between us.

She answered after a single ring.

And she immediately began with this:

"Sob... Hic. Hewwo? Satori...?"

"Ehh!? Why are you crying that much, mom!?"

"Do I really have to spell it out for you? Kh, wahhhh!!"

This was odd.

My mental image of that parent was crumbling. Would a legendary demon lord really cry like that?

"Umm, I'm not sure how to say this...but sorry."

"And what are you apologizing for!? That's important, so tell me!!"

I could tell this was going to be a huge pain, but she at least seemed okay.

I had calmed down enough to realize I was essentially calling home in a panic after having a bad dream, but this was no laughing matter.

"Mom, I have a question."

"Where are you? Can I go meet you?"

...

"That would probably lead to another chainsaw rampage, so no."

"Hm? Chainsaw...???"

Crap, I shouldn't have given her that hint.

"Mom, would you know what it meant if someone was dragged into a glowing ocean and pursued by a giant shark?"

"Explain."

I did as she asked, but I felt like I was wasting my time. She reacted like this was her first time hearing any of it.

"Sniffle, a giant shark Archenemy, hm?"

"Maxwell said there aren't many varieties of those even though they're a horror standard."

"If it's a shark, yes." She seemed to be hinting at something. "Okay, Satori. Before beginning this Archenemy discussion, let's start with some basic information on sharks. First up, what does the word shark bring to mind for you?"

"A huge carnivorous ocean fish."

"Such as the great white?"

"Also caviar and shark fins."

"The sturgeons of caviar are not actually sharks...but it is true that gives sharks an image of being tasty. Even if actual shark meat is not eaten much."

She seemed to be smiling, but she did not cut me off either. I sensed satisfaction, as if she knew I was headed in the direction she wanted.

But where was this seemingly pointless conversation leading?

"Hey, Satori. My point here is not how sharks behave or how most of them eat only plankton or small fish and few are actually man-eating. Your general image of them is what matters."

"Um?"

"You think of them as the largest carnivorous ocean fish and a rare ingredient. ...So there was no need to insist on it being a shark. It's just that a shark is the first thing the general public will think of when picturing that being who is spoken of on a mythical scale."

"Hm? Hmm???"

"You know the giraffe and the legendary Kirin are different, right? The tapir and the Baku also work."

"Well...yeah, I guess..."

I didn't know much about it, but I vaguely remembered seeing a logo like that on the beer cans my dad and stepmom drank.

"The legend came first and the animal was discovered later," explained my stepmom. "A connection was assumed since it sort of fit the legend's description, but their roots are actually unrelated. Some animals end up in that odd mixture of legend and reality. In this case, it's 'the world's largest fish and an extremely rare ingredient'. Heh heh heh. It's important to remember that it's a fish and not a mammal. That's why it has to be a shark and not a killer whale."

What did that mean?

What were humans mistaking with what if that giant shark seemed like an acceptable answer?

"You still don't understand?"

I just wanted an answer.

And my stepmom finally gave it to me.

"The Leviathan. The greatest and strongest demon lord and an offering which god created along with the Behemoth to fill the mouths of all the apocalypse's survivors."

Even after she gave it, the scale of the answer was so great that I failed to understand.

"Levi-what? Why would something like that be hanging around a far eastern island nation?"

"You say that, but your own mother is Archenemy Lilith."

Dammit, famous people just have no sense of scale! I feel like I asked someone how to make friends with a Hollywood celebrity and got the answer "go for a stroll along the usual route in Beverly Hills" with a straight face!!

"I can't really tell you much for sure right now," said my stepmom. "I can't think of any legends or myths related to being dragged into an illusion or glowing ocean to be hunted. Maybe it's related to the Leviathan's ability to breathe fire and smoke. But..."

"...There's more?"

"The Leviathan may have chosen Kukyou City for commemorative reasons. In other words, sightseeing. ...After all, this is where anti-Archenemy Bright Cross was destroyed."

...That implied it was me who had invited it here.

But hadn't the witnesses accounts of the Leviathan dated back more than a month and thus before the Bright Cross's destruction?

"Also, it seems the Leviathan corresponds to envy of the seven deadly sins. Incidentally, Lilith (that's me) corresponds to sloth."

"So you're both powerful demon lords?"

"Yes, but there are more than 7 of us. Different theories place different demons in each spot, so the total number is too much to count on your fingers. Kind of like when you mass produce 'strongest' protagonists, the meaning of 'strongest' begins to fade. So it wouldn't surprise me if a demon lord wanted to settle things once and for all. After all, we stand at the very top of all those eeeevil demons."

"..."

"Your involvement may be a way of challenging me."

Part 2

It was lucky I was using a cellphone.

I never would have gotten past my stepmom's stubbornness without my special attack: "Ah, the signal just dropped to one bar. Hello? Mom? Hello!?"

"I guarantee you she saw right through that," said Maxwell.

"Really?"

I ended up spending the night at my mom's apartment, but I barely slept. I was given the guest room which was clean but smelled of insecticide and I dozed off a couple of times. But every time, I dreamed I was falling into emptiness and woke right back up.

I eventually noticed the morning sun entering through the crack of the curtain. The clock on the bedside table said it was just before 6 in the morning. On a floor this high up, you apparently could not hear the birds chirping.

"That was worse than I expected..."

After muttering that on the bed, I left the guest room. My throat was parched. Trembling in fear all night while terrified of water was rough on the body.

I borrowed a glass cup from the kitchen and turned the knob for the faucet which had a water purifier attached. The clear liquid poured in like normal, but I could see the water's surface wavering because my fingers were trembling a bit as they grasped the cup.

It would be fine.

What did this matter?

I pressed the edge of the cup to my lips and tilted my head back to pour it all down my throat at once. I could feel something permeating my body starting from my throat. I felt like I had consumed the fear and made it mine. I began to think humans might have gone out of their way to hunt large beasts and sea creatures as a ceremony for conquering their fear and transforming it into their own flesh and blood.

"Morning..."

I heard a door open and a yawning voice. It was Himatsuri-san rather than my mom. She apparently really was living here. She did not have her hair up like a fancy peacock or fruits first thing in the morning, but her blonde hair still looked Medusa-ish while down.

She apparently slept in a baggy dress shirt, but whose was it supposed to be?

"Taori-san doesn't eat breakfast, so there's no use waiting for her. If you're hungry you'll have to grab something from the fridge."

"Sure."

She had made breakfast every morning when I was little...so had that been a burden on her? I realized I had never really worked in the kitchen. Food was just something that had appeared as a matter of course.

Himatsuri-san followed her own advice and opened the fridge even though this was not her home.

"Kh."

Her shoulders tensed. Curious, I looked over her shoulder and realized her eyes were locked on the 2-liter bottle of mineral water lined up alongside the milk and orange juice.

Water.

The entrance to that death game.

We hadn't said much about it, but she had been caught in that problem too, hadn't she?

"..."

I couldn't blame her for being nervous and everyone conquered fear in their own way. I started to leave the empty cup in the sink, but then I reached for the sponge. Mom wasn't my servant, so I couldn't just leave all the work with her.

"How can you get your hands wet like that?" asked Himatsuri-san.

"I'll admit I'm afraid, but I can't avoid it forever."

"Uuh..."

"And aren't all of life's necessities reliant on water? You need it to drink and bathe, but also for laundry and the bathroom..."

"Dammit, what are we going to do?"

We would enter it, fall into it, and be dragged into it.

The depth was irrelevant. If the surface area was all that mattered, a roadside puddle would be a threat. It was true we had to watch out for water of that size. Even the thin layer of water in the sink was dangerous. But we would dry up if we were too afraid to do anything.

"I'll have orange...no, apple juice."

Himatsuri-san's hand indecisively wandered between options before grabbing a large paper package. I honestly didn't see how it mattered and it seemed no more important than putting a colorful additive in the bath, but it may have been a necessary ritual for her.

She then sat directly on the stainless steel countertop and spoke to me.

"Now, boy?"

"What?"

"...To be blunt, what are we going to do? We're stuck having to outrun that shark. It can only happen once per day, but there is no advance warning and you never know when it will happen. That's honestly too much to bear."

It would be for anyone. I never wanted to experience that again and I wanted to try every way I could of avoiding it.

Staying uninvolved would of course be best.

If we did not touch water, we could avoid the shark.

...But was that really enough? I felt like I was just trying not to think about it, like someone who was too afraid of an earthquake or typhoon to plan for what they would do in the event of one.

I knew the best course of action.

But shouldn't I also consider the second-best?

"To be blunt," I said.

"Yes?"

"I don't know what route you took, but I barely made it. I don't think I had any real control over where I went."

The view down from the 8th-floor bath window had seemed entirely hopeless. That might have been different if I had a way of crossing between buildings in that flooded city.

" 'today's exit'. We need to think about a situation where that door is located out of reach or where the emergency stairs leading up to it are destroyed by the storm or shark. I think our most pressing need is some means of moving through that flooded city."

A vinyl rope folded over several times would support our weight and it would fit in a bag while rolled up.

...And we fell into that demon lord's ocean when we were dragged down into the water. If we did it right, we might be able to tie ourselves to something to prevent us from falling in the first place.

"I guess we can't just defeat that shark and live happily ever after, can we?"

"Well, no."

For one thing, the shark was the size of a submarine at more than 30 meters long. Even a close-range shotgun blast would probably be stopped by its thick muscles and fat. I couldn't imagine accomplishing anything by swinging around a bicycle or street sign from the city. Or were we supposed to live in fear of that glowing ocean while carrying around a bazooka at all times. If we walked around town with one of those, we would be the ones seen as monsters.

...It might sound silly, but society was a nuisance in something like this. It was kind of ironic that such a ridiculous being was using the normal social system to make us suffer.

That suggested this wasn't just an animal. It was an intelligent Archenemy.

"But why us?" asked Himatsuri-san while sitting on the countertop with a hand on her chin.

...I decided it was best not to mention the possibility that this was triggered by the Bright Cross's destruction or because the Leviathan and my stepmom were both demon lords of the seven deadly sins.

Besides, those reasons might not even explain it.

They would explain why the Leviathan was after me or my stepmom, but not why Himatsuri-san was also affected. Plus, the witness accounts dated back to over a month ago, before the Bright Cross was destroyed. So it was not simply spreading from my stepmom and me. Despite what my stepmom had said, the Leviathan's behavior pattern here was still entirely unknown.

"Whatever we do, let's just hope we survive until tomorrow."

"Agreed."

In order to report on our survival, Himatsuri-san and I exchanged smartphone addresses.

How many people had been involved in that the day before? And how many had failed to return? It was possible the survivors category was the smaller of the two. It looked like I really needed to look through some old incident reports.

Part 3

The previous day had ended.

They had reloaded. I could be dragged down into some water at any time, so it was no time to be casually attending school. I had to assume it would happen again today, so I needed to be prepared.

I used my smartphone and an ATM to withdraw the savings I had built up in an online bank account from my allowance and I gathered the necessary items at a nearby hardware store.

I then walked to a container yard along the harbor.

"Maxwell. If you ignore the laws governing EM signals, how far could a signal reach from an independent home server that doesn't rely on the cell towers?"

"Sure. If the limiters are fully removed, it could reach a radius of 20km while stable or around 30km while spottier. However, this would drain the battery, hasten deterioration of the parts, and leave no guarantee for the user's health."

"20km, huh? That's good enough. If that isn't enough to reach the mountains, I guess I would have to attach an amplifier or expand the antenna with wires or a wire hangar."

"? Either way, those settings are not recommended. Might I ask what you intend to do with this?"

"There was a city-wide blackout when I was fighting the shark. I don't know if the flooding or the storm is to blame, but it means I can't rely on normal sources of power or communication."

The smartphone itself worked since it ran off a battery, but the cell tower was hooked up to the power grid. Even when you called someone a meter away from you, the signal was not passed directly between your phones; it was sent to a cell tower and back. So with that cell tower down, the connection between Maxwell and my smartphone was severed.

For household devices to directly communicate, you needed a home server. They were meant to wirelessly manage pre-authorized game systems and DVRs, but that would be enough to provide a direct link between Maxwell and my smartphone.

That just left one other problem.

I rapped on the metal surface of a container.

"You're already somewhat waterproof, but it's really just adding a rubber seal to the door so rain doesn't get in during a windy storm. ...I'm going to spend today on some construction. I need to make sure you won't be crushed by the water pressure when it floods to a height of five stories."

"No. That is not as simple as it sounds. You might think it will be the same as waterproofing a watch, but a lot more strength is needed to protect an open space as large as this."

"True, but who said I was building a submarine?"

I set down the large paper bag from the hardware store.

This large space is already filled with air like a balloon. If I make sure no water can leak in and I detach the latches holding it to the ground, won't it float up to the top of the floodwater? Just like a beach ball full of air. And you use liquid cooling, so making it airtight won't cause you to overheat."

Well, it was not quite that simple since I couldn't have the container floating away or flipping over. It would need a thick chain and some weights on the bottom, like a self-righting doll.

"What about the power supply?" asked Maxwell.

"The actual shark pursuit won't last long. Only 10 to...yes, let's say 30 minutes. Any longer than that and I'll be eaten and killed."

Maxwell was handmade by connecting 1400 handheld game system cores in parallel, so the inside was a complete mess of power cords. I had gotten an industrial power supply sent in since a normal socket was not enough, but a large lithium-ion battery would probably be enough for such a short time frame.

I couldn't afford electric car parts, but a few battery packs for an electrically-assisted bicycle would mean a lot. I had to pay careful attention to the voltage and amperage, though.

"It is strange to make preparations in the real world to provide greater freedom at unknown coordinates that may not even exist," said Maxwell.

"Tell me about it. If I could only know in advance what door would be designated the exit, I could place ladders on the walls and plywood between building roofs to construct a route, but I guess I can't hope for that much."

If the glowing ocean was overwritten onto the real world's data, then this would work. Whether or not I could use Maxwell in that flooded city hinged on that. This was a lifeline I could not afford to let slip away.

I had to protect Maxwell and the cooling container.

I said one last thing as I pulled out the thickest chain the hardware store had to offer. It was the kind used to keep cars out of a park.

"It's been a while, but it's time for another episode in our amusing construction projects series."

Part 4

"Fuguu."

While I was working up a sweat cutting the thick chain with wire cutters that looked like a monstrous version of nippers, a strange voice rang through the coastal container yard.

It was Ayumi, my stepsister with a twin butter roll hairstyle.

Since the zombie showed up in her uniform, school must have let out. I checked my smartphone to find it was half past 4. I had completely forgotten to eat lunch. The sky had grown cloudy while I wasn't paying attention.

"Onii-chan, why are you chaining up Maxwell? Do you like tying up your favorites?"

"I have problems to deal with."

"And so do we! You need to come home. Mom is acting all depressed and she's so out of it that her housework skills have plummeted."

That was probably how it looked since I had kept the trouble from spreading to the rest of the family. I was standing at a fairly important crossroads for my life, but Ayumi didn't seem to care.

"The laundry is piling up and we were only given cup noodles for breakfast. For breakfast!! If every meal is like this, we won't last three days."

"I notice that you cooking doesn't seem to be an option."

"I don't want to hear that from you, Onii-chan."

She had a point.

It hit me that kids were really reliant on the word "normal".

"It's not fair to make mom cook all the time, so maybe I should start eating out from now on. Maxwell, we could earn some money renting out your processing power, right? Like for calculating the aerodynamics of experimental cars."

"Don't do that. Mom really will start to grow horns."

Ayumi cut in while speaking rapidly and she looked up at the container skeptically.

"And what are you doing anyway? It's unhealthy to be surrounded by this strong adhesive smell."

"I know what you're saying, but I had to improve the waterproofing in a hurry. ...And I've just finished."

I gave the chain a lot of excess length and wrapped it around the stake driven into the ground. Then I nodded.

I had already finished the work on the container itself. In fact, I had only needed to check over the most important points and fill them in with thick rubber adhesive.

"Onii-chan, what are you going to do today?"

"Good question."

I had to choose whether I would sleep at my mom's apartment or my actual home, but then something occurred to me.

...Was it possible Himatsuri-san had been affected because of her proximity to me?

This seemed to have begun more than a month before I got involved, but the rules were still a mystery. The risk would be the same if it turned out the victims were all people I had passed by on the streets.

The risk of the people I cared for getting dragged into this, that is.

That meant I couldn't rely on either location.

"There's something I want to test out, so I'll be getting some sleep here. And I don't know what I'll do tomorrow."

"No!! You're dooming us to cup noodles tonight!!"

"Go beg Erika to cook."

"Onee-chan is just as out of it as mom, you idiot!!"

But that was all the more reason why I couldn't get Ayumi or Erika caught up in this mess. My vampire older sister would be at the most risk in that flooded battlefield because she could not cross running water. I had even done something similar to her in virtual reality.

Just then, I felt something cold hit the tip of my nose.

"Fugu?"

Ayumi made a weird noise and looked up. Thick clouds covered the sky. Those gray rainclouds had grown much darker and clear raindrops were falling from them.

It took no time at all.

"Unyah!?"

"Oh, no. Maxwell!!"

The sudden downpour pounded on the ground. This went beyond just avoiding puddles. The world was transformed in just 5 or 10 seconds. It was like the ground had become a dull and earthen mirror.

It was a giant surface of water.

And it could drag people into that glowing ocean.

"Eh? Ah...Onii-cha-!?"

I couldn't even hear Ayumi through to the end. With nothing to grab onto, I fell straight down like I had stepped on a pitfall.

Part 5

The world suddenly flipped upside down. I couldn't open my eyes or breathe. It was tossed about by an incredible force and I just barely managed to grasp that I was in a powerful current.

"Gbah!"

Once I realized that, I felt intense pain in my eyes, nose, and mouth. The taste and pain was like having salt directly rubbed all over me.

"Cough, cough!! Cough!! Gwoh!?"

It was that submerged and glowing hell. But the starting line was not a high-rise apartment this time. Was it really this much of a disadvantage to start on the ground!?

...Anyway.

I had to get up. To the surface. But which way was up!? Where did I have to go to be reunited with the air like normal!?

While I sat around, unable to do anything, I felt an explosion of heat in the core of my mind. I had no oxygen. Strength left my limbs and I was unable to resist while the salty current swept me away.

But that may have worked in my favor.

I had heard that humans were naturally buoyant, so the reason poor swimmers sank was because their fear of water caused them to subconsciously tense up.

For whatever reason, my face breached the surface of the raging water.

"Gasp!! Cough, cough!!"

I had reached the oxygen I longed for, but my lungs refused to breathe it in. Opening my mouth only let wet coughs out.

Even so, strength returned to my limbs.

Afraid of losing this natural buoyancy, I flailed my arms around. My fingertips happened to find something hard. ...A metal container? It was not sticking up from the depths like the high-rise apartment had. The pyramid of containers must have collapsed and the ones with air pockets inside had floated up separately.

As for Maxwell...I couldn't tell one container from another. I just held on tight to the edge of the container that's square roof just barely rose above the water's surface and I climbed on top.

"Pant, pant!!"

I rolled onto my back, sprawled out my limbs, and finally managed to truly fill my lungs with air. Calm down. You'll be fine. You experienced the flooded city in the simulator and this is the same. I shook my woozy head and found thick, dark clouds and blowing rain just like before. But perhaps because the sun had yet to set, the sticky blue glow of the water seemed weaker than before.

...Oh, right.

The blue light reminded me: Where was that map? Where was 'today's exit'? It was supposedly drawn on windows and mirrors using the liquid and water droplets.

"Are you kidding me?"

I got up and observed my surroundings. There was nothing but a dirt-colored torrent surrounding me. That and the metal containers floating and sinking within the complexly intertwining waves. I couldn't see a map. In fact, I couldn't see any shiny windows or mirrors at all.

An impossible scenario was a possibility.

That part of the rumor came to mind. This was bad. Since the demon lord's ocean was based on the real city, the mirrors and windows would not be evenly distributed. A ballet classroom would have a giant mirror covering a whole wall while a container yard was much less promising.

"Goddammit! Maxwell!!"

"Sure. Do you have a specific request?"

I could get help from Maxwell using my smartphone, but Maxwell would not know the location of today's exit.

I heard the sound of parting water.

When I hesitantly looked back from atop the rocking container, I saw...something. The distant water was being sliced apart by something like a sharp and sinister triangle of rock larger than the average tent.

...Is that a shark fin?

You're kidding right? Please tell me this is a joke!

The fact that it was completely motionless made it even creepier. Wouldn't a bigger body mean the current affected it more? Were its muscles powerful enough to defy nature or was it reducing the effects with special scales?

"I just want to get out of here!! Put together a route!! How do I get away from the water's surface!?"

"Sure. The fastest route would be to climb up the gantry crane used to carry containers."

I couldn't wait any longer.

I didn't have time to be trapped by common fear in this absurd and unreasonable place.

I took a running start.

The container rocked up and down like an unsteady boat, but it was the size of a small bus. I ran and I leaped.

The containers of the collapsed pyramid were floating here and there like cherry blossom petals on a lake.

If I fell in the water, I would be in the giant shark's — the Leviathan's — territory. So I had to jump from container to container no matter how unreliable they might seem.

Something like a loud roar hit me in the back. Did sharks roar? Or was that the sound of the air as that exceptionally large body moved around? I doubted I would have an answer anytime soon.

I honestly didn't have time for distractions, but I still looked back. How fast could sharks move again? It seemed strange it hadn't caught up yet, but I caught sight of something when I looked back.

"What? Is it randomly biting into all the containers floating in the water?"

"Sure. Sharks do not have very good eyesight, so they pursue their prey based on the scent of blood in the seawater or the bioelectricity escaping the prey's body."

"Are the metal containers messing with the flow of electricity? Or is it mistaking the smell of rust for blood?"

"The details are unclear, but it can likely distinguish the real thing from a fake if it can compare the two. In other words, this unintentional decoy will likely only work for as long as you have not fallen into the ocean."

It almost scared me how lucky I had been, but even with these cards dealt to me, safety was not guaranteed. The Leviathan was destroying all of the containers while approaching. If I stayed still, I would lose my floating island and end up in the water. Once that happened, the giant shark would leave that forest of illusion and make a beeline for the drowning raw meat.

That left just one option.

I could not stop running. I had to jump from container to container and escape far enough inland that the giant shark couldn’t reach me! I-i-i-it’ll be fine. You saw this flooded scenery when you fought your vampire older sister in the simulator! The giant gantry crane overhead looked like safe ground, but if the giant shark jumped from the water while I climbed the work ladder, I would be killed instantly by its teeth. And the Leviathan was more than 30 meters long and had enough strength and weight to tear right through my mom’s apartment building. Even if I was lucky enough to reach the control cabin at the top of the gantry crane, it would probably break right through the steel pillar and send me tumbling down into the water.

Thinking about that caused the gantry crane’s presence to grow in my mind.

Holing up there would accomplish nothing, but the crane’s controls were there. Yes, and they were contained in a transparent box surrounded by reinforced glass panels, just like a phone booth.

And the location of the one-and-only orange-glowing exit would be drawn in blue light on any kind of window or mirror.

“Maxwell! Use the zoom to photograph the gantry crane’s control cabin. And analyze the image for anything visible in the windows!!”

“Sure. I have detected the same diagram in all six surfaces. It appears to be some kind of hand-drawn map. Comparing to a road map of Kukyou City…searching for matching conditions…”

I of course had no time to wait around. The submarine-sized killer shark was approaching from behind while chomping through the metal containers like popcorn. My life was on the line here. With the wind blowing against me, I stepped on the slippery metal roofs and continued jumping from container to container as they rocked in the waves. If I fell just once or was slowed by just ten seconds, my fate was sealed. My chest hurt as my heart pounded harder than necessary.

“Corresponding location found. It is a section of the harbor sightseeing district’s harbor industrial region. It is a popular spot for an industrial tour that views the scene from a ship at night and…”

“Get to the point! I don’t have time for all this!!”

“Sure. Please move 200m northwest using the current container route. The ‘today’s exit’ label points to a maintenance hatch on the side of a smokestack on Hanaoka Heavy Steel Industrial Complex’s Building C Blast Furnace.”

“Still too much detail!”

“I suggest you learn how to read between the lines. I am saying you will be able to return if you climb the spiral staircase wrapped around the giant smokestack like a morning glory vine and open the door along the way.”

I arrived at the industrial complex before I finished reading Maxwell’s text. My jumping from container to container was weak-kneed, but the containers themselves were being swept along by the current all the while. It may have been like riding the moving sidewalk at an airport.

Luck was on my side.

My life was receiving a tailwind at the moment. Or so I wanted to believe.

With the dirt-colored water swallowing everything up, it was impossible to tell the land from the ocean in the harbor block. But the tall smokestacks rose up like a forest.

I was still not blessed with any solid ground and forced to jump between containers, but then something appeared in the corner of my eye.

Someone was converging on my path while following the containers from a different direction.

“Himatsuri-san!?”

“Oh, it’s the kid. Did you get dragged in here too?”

I didn’t know if she dyed it or bleached it, but her long blonde hair was done up in that cabaret girl way and she wore a champagne-colored dress that showed off bodylines you wouldn’t find in a high schooler. I realized I really didn’t know much about her. I was impressed she could pull off those killer athletic moves in such a frilly dress though. But the fact that I had run across Himatsuri Asami here held an important meaning.

…We could share this fear. We did not all have separate dreams. All of the participants were making their way to the same “today’s exit” door. And since both of us had survived the day before, did that mean the door was not a one-use thing for the first person who reached it?

The conditions could be impossible. It was like being forced to play a game of Russian roulette until someone blew their brains out.

I could see how that would happen. It was entirely possible that you would be forced to cut across the entire city from west to east. And while traveling through the flooded and stormy city with a giant shark chasing after you. Depending on where you started, your odds of survival could drop almost to zero. And your own effort could not change that percentage.

“How did you figure out it was this industrial complex from that ugly hand-drawn map?”

“The human mind gets a boost when your life is on the line. I just happened to remember seeing that layout on a field trip when I was younger. I think I even showed off a photo of it to that girl.”

…My mind didn’t seem to get that kind of boost, but that may have been because I had Maxwell. Just like how the ability to read and write kanji declined thanks to IMEs, a convenient agent could be a harmful thing. Himatsuri-san’s mind was still analog, so she may have had her life flash before her eyes.

The sound of metal being chewed reached us from behind.

Oh, no. That’s a lot closer than before. The giant shark had been chewing through the floating containers seemingly at random, but it was still the lord of the sea. Running and jumping might not be enough to escape.

But even that proved to be naïve.

This time it did not “sound like” an explosion. An actual explosion burst behind us.

I was confused.

I nearly fell flat on my face as the blast pushed on my back, but I managed to stop myself and regained my balance on all fours. Himatsuri-san in her wet dress completely tripped and fell, so I quickly jumped on top of her. It was all over if she rolled off and into the water.

We held each other and hesitantly looked back. Sticky orange flames covered the wavy surface of the dirt-colored water.

“An explosion…? Was it the oil used at the industrial complex…???”

Had the tanks of oil been floating in the waves just like the containers? Had they hit the giant shark, or had it bit into one of them?

Whatever the case, it did not end there.

While the water burned like the ocean at sunset, that sharp rock of a fin silently slid toward us. The intense current meant nothing, so it felt entirely removed from the laws of physics.

“Does none of it matter, dammit!?”

We had to flee.

More and more intense explosions followed the Leviathan’s path while we continued jumping between containers to reach the smokestack. We still had a ways to go, but the shockwaves of the explosions were sapping our strength. At times, the sticky flames would fly in an arch and pass over our heads. It seemed to be something like a Molotov cocktail, so we had to change our route across the containers or have the flammable substance poured down on our heads, setting us ablaze.

I had assumed a police officer’s handgun would not be enough to stop it.

But I had never imagined it would be this tough. It really was an Archenemy instead of a mere shark. It swam around just fine despite the explosions covering the industrial complex in flames, so I wouldn’t have had the guts to challenge it with a flamethrower or bazooka!!

“Himatsuri-san!!”

“That’s it, isn’t it!?”

We approached a group of gray towers spaced evenly like roadside trees. Their diameter was probably about the size of a classroom. Rusted metal spiral staircases wrapped around the sides of the giant cylindrical smokestacks like a barber’s pole.

To be honest, all of the smokestacks were identical.

So I looked further up while jumping between containers.

There it was.

One of the metal doors spaced at even vertical intervals was glowing orange.

And I checked the writing printed large on the smokestack’s side.

“Building C Blast Furnace! It’s the fourth door from the top!!”

I did not count from the bottom because I couldn’t see the bottom due to the flooding. We had to climb over the railing to reach the portion of the spiral staircase rising above the water. We had to be starting at more than 5 stories up already.

We jumped over.

Even as we ran up the spiral staircase from just above water level, we could still hear muffled explosions from the water below. At the same time, we felt an intense mass of heat rising up toward us.

Himatsuri-san glanced over the railing and gave a hesitant comment.

“A stove’s heat rises, doesn’t it? I hope this isn’t going to cook us.”

That thought made me shudder. I didn’t want a giant brute-strength shark to have that kind of intelligence.

But I should have given it more thought.

Yes, this thing specialized in brute strength.

A moment later, our footing shook violently. No, it didn’t just shake. The entire world had begun tilting!?

“Is he tackling the building to break the entire blast furnace from its base!?”

“Seriously!?” shouted Himatsuri-san as she ran. “But this has got to be sturdier than the Leaning Tower of Pisa!”

Meanwhile, another blow hit. This destruction required coming to a complete stop in that torrent of water and taking careful aim. We were already quite high up. If we fell, there could be something sticking out of the water there, but even just hitting the water would be dangerous. Especially when there was a submarine-sized shark in there.

“What do we do!?”

“We can’t beat that thing if we head back down! We might be able to use this height as a weapon, but we don’t have any rocks or stones to throw down at it!”

“Then what do we do!?”

“We get through that door before the smokestack collapses. What else can we do!?”

The metal stairs creaked disconcertingly as we ran up them two steps at time.

We finally reached the door we needed.

Guided by the orange light brightly decorating its surface, we tried to push it open with our shoulders…and then we realized something.

We heard a creaking sound, but it would not budge. The metal door wouldn’t open!

“A-are you joking!? Please don’t do this to us!”

“This is no joke! It really is locked!”

Was this due to the battlefield being based on the real world? But there was no turning back. We did not have time to search the flooded industrial complex for the key.

32 grams of an aluminum and zinc alloy meant all the world right now.

But we couldn’t let it matter.

Himatsuri-san and I exchanged a glance and then kicked the door as hard as we could with the soles of our shoes. It produced a loud noise. At the same time, the entire smokestack tilted to the right. It was definitely falling now. My spine froze, but I forced down the fear and tried again. As many times as it would take!

With a loud bang, I felt the lock breaking. The metal door flew open the other way.

We could not wait any longer.

We practically rolled through the door.

Part 6

It was the worst feeling.

“Cough, cough, cough.”

I was pulled back to reality by the unhealthy scent of burning oil. Himatsuri-san and I were soaked with seawater and we were in the maintenance entrance to a blast furnace in an industrial complex that would be off limits to the public. If we were found here, it would not be seen as a mere prank. We might be mistaken for terrorists planning a largescale conflagration or to pollute the ocean.

But we had made it back.

We looked back and saw the metal door firmly locked despite having kicked it down a moment before. No matter what that shark destroyed in the glowing ocean, it would not affect the real world, so the door was still a door.

…We had been lucky again this time.

What if the designated door had led to a women’s bathroom, a women’s locker room, or the Class Rep’s bath? I couldn’t imagine what kind of explanation would convince anyone I hadn’t been up to no good.

“I wonder what happened on the other side,” quietly said Himatsuri-san while looking at the metal door. “That smokestack was clearly falling. We made it in time, but…”

Yes, that was right. Since Himatsuri-san and I had been working together, all of the participants would have been gathered in that single demon lord’s ocean. So couldn’t there have been more people there than just us?

“The smokestack collapsed, but they might be fine as long as they can get through the door.”

That had to be true. If the door counted as the goal regardless of the state of the building around it, then it wouldn’t matter if the smokestack was standing or not.

“But no one would know where it was if the smokestack was broken to pieces, right? If the door sank to the bottom of the water, it wouldn’t be easy to find…”

“…”

I knew what she a saying. Simply approaching the exit would be difficult if they had to dive down into that water with so much wreckage strewn everywhere. And the water was the Leviathan’s territory. Whatever the case, the difficulty level would be very different from when we passed through.

We had been lucky.

That was all there was to it. And while today’s was complete, no one could say how lucky we would be tomorrow.

“…We can’t keep this up.”

[Self Record] A Science Magazine Column [Leviathan’s Record]

Animal evolution is said to have begun in the sea, emerged onto dry ground, and finally reached the sky.

But what have animals gained from that grand evolution?

For one thing, even after emerging onto dry ground, animals can never escape the sea no matter how hard they try. That is true even in an inland desert nowhere near the sea. You cannot discuss the conditions for rainfall or groundwater without bringing up the oceans that cover the majority of the planet.

Was it the cleverest of the animals that sought dry land? Or were the clever ones the ones that saw that as wasted effort and remained in the sea?

When you view the chaos of the modern age, it can be hard to say.

Chapter 2

Part 1

It was a good thing I had my waterproof smartphone. Without Maxwell, we may not have been able to safely leave the blast furnace, not to mention avoiding the workers while we did so.

Since I was with Himatsuri-san, I naturally returned to that high-rise apartment building where my mom, Magatsu Taori, lived.

But late at night after midnight, a vampire visited at the 8th floor window.

“Satooori-kun.”

“Erika.”

“You need a serious lecturing, so prepare yourself.”

When she said that, I could only seat myself in front of my sister who had gorgeous blonde ringlet curls. That vampire sister was part of the nocturnal group, so she should have been at school at this time. That meant she had skipped school to pay me a visit, so I couldn’t just refuse her.

She must have been quite angry and unable to control her emotions because she put her hands on the hips of her black gothic lolita dress, looked down on me, rudely pointed right at my nose over and over, and finally hugged me for some reason.

But.

“Ayumi-chan was in quite a panic after seeing you disappear, so you need to go speak with her later.”

…Telling my family I was safe was embarrassing, but I had to do it.

“Since Ayumi wasn’t taken with me, it looks like only the people targeted by that giant shark, the Leviathan, are dragged into the glowing ocean. That’s a relief at least.”

“…But this doesn’t really make sense.”

“You thought so too?”

“Yes. If the Leviathan is trying to attack mom over the seven deadly sins stuff, then it should have targeted Archenemy Lilith first and foremost. Even if it specializes in trickery or harassment, it’s hard to imagine why it would target you but overlook Ayumi-chan. You’re both mom’s family after all.”

…That was right.

If the Leviathan’s goal was to take away the people important to my stepmom, it would have taken Ayumi as well. And it would have no reason to continue targeting Himatsuri Asami.

“This might have nothing to do with the seven deadly sins. Could there be some other reason why it would attack just the humans of Kukyou City like Himatsuri-san and me?”

“Come to think of it, mom, Ayumi-chan, and I are all Archenemies. …It could also be that the power to drag people into that lost sea only works on humans.”

In that case, the harassment theory returned. It might want to target Amatsu Yurina, aka Archenemy Lilith, but could not. And the same was true of a vampire like Erika and a zombie like Ayumi. That was why it targeted a close relative like me who was a pure human or other people who lived in the same city as her.

The way I kept shifting from one theory to another showed how little confidence I had, but it was also because this was very important and I could not let myself settle on an answer to easily. I made a mental note of this meaningful blank in my knowledge.

“So what are you going to do now, Satori-kun?”

Erika asked that fundamental question while sitting on the bed next to me. And I knew she was not asking about where I would spend the next night.

“If you fall into that lost sea when you contact water, it seems to me you could stop it by tying a rope around your waist and typing the other end to some sturdy piece of furniture like a bed or dresser.”

“I considered that.” I sighed. “But I don’t know the exact conditions for what is carried over to the other side. If the furniture or column is dragged down with me, it would only weigh me down. That would make it hard to escape the Leviathan, but it would also prevent me from getting above the water if I started in a flooded area. I’ve already experienced a start from the surface, but this would be even worse.”

“I see.”

I of course only had one life. No matter what absurd challenge awaited me, it was all over if I died. I would not last if I attempted a trial and error method in that extreme environment. And we had so little data on that glowing hell that it would be difficult for Maxwell to put together a simulation.

“I also considered staying in a small room with no water. I would of course need drinking water in a sealed container with a straw opening.”

“Right.”

“But the problem is that the Leviathan is targeting me for some reason. This isn’t random. So if I find some way of escaping from that hell, I doubt it will just sit idly by.”

“But I thought the Leviathan could only harm you after pulling you into that lost sea?”

“Have you forgotten, Erika? It can pull other people in there as well.”

“Oh. And in that case…”

“It might use other people to rob us of any safety we find in reality. I haven’t seen that giant shark speak, but it could probably carve writing across a building wall if it wanted to.”

We were up against an Archenemy.

Whatever it looked like, I had to assume it had at least human level intelligence. Whether it also had enough of a conscience to communicate properly was a different matter.

High intelligence did not always lead to a spirit of mercy and benevolence. In fact, animals that – just like humans – harmed others for fun instead of food or defense were much rarer than ones that would commit suicide to protect the food cycle of their group.

“You mean it could make a threat like, ‘Splash water on Amatsu Satori to bring him to me. Otherwise I will continue targeting you day after day and night after night.’?”

“Just like me, they only have one life and can’t use trial and error tactics. The Leviathan might intend to kill them all anyway, but the other participants would have no way of knowing that. Most of them probably wouldn’t know who ‘Amatsu Satori’ is, but if it keeps making the demand and killing them, it will eventually come across someone who knows who I am. This is all happening in the one city, after all.”

With those methods, it didn’t particularly matter if I had water near me or not. Some malicious person could bring the water to me.

And I wanted to avoid a situation where people were being indiscriminately killed in order to harm me.

As I had thought before, just not touching water would be best. But I was afraid of never considering anything beyond that. I also had to think of a way to survive if I did run across that giant shark.

I had started at my mom’s elevated apartment and the ground level coastal container yard, so I knew just how much the starting point could change things. If I visited the hardware store and some discount stores, I would probably see a treasure trove I had not noticed the day before.

Part 2

And another thing.

“Hi.”

“Himatsuri-san.”

On Erika’s insistence, I went to school for the day, so it was afterschool. We had agreed to meet in front of a large discount store in the harbor sightseeing district’s shopping area, so I saw Himatsuri Asami-san’s incredibly gal-ish hair and champagne-colored dress.

We entered together and she asked me a question.

“So how are we going to attack this problem?”

Carrying the shopping basket seemed to be my job by default. She had a natural swagger to her walk and I could just hear her saying she refused to carry anything heavier than a handbag. She seemed like the type to only have cards in her wallet.

“Looking back, I think we were pretty passive last time.”

“What do you mean?”

“We’re moving between two different areas, but we were too hesitant to mess with things on the other side. It’s not like anyone’s going to get mad at us if we smash and destroy things there.”

That hesitation may have come from it looking just like the city we lived in. But the real scenery did not change even when some buildings collapsed in that glowing ocean. The industrial complex had received the double punch of the flooding and the flames, but there was nothing in the news back in reality. We were worried about that world for nothing.

Himatsuri-san turned to the side to slip through the gap between shelves of makeup and candy that stuck out a fair bit. Her shapely breasts nearly bumped into the products as she spoke up like she had just remembered something.

“Come to think of it, we barely made it last time. Especially with that smokestack door at the end! We would’ve been screwed if kicking it down hadn’t worked!!”

“Yes, which reminds me.”

I wanted a crowbar or some other item that would use leverage to break open most any door. …Carrying around an actual crowbar would not end well if we were questioned by the police, so I wanted something else that could accomplish the same thing.

“We also need some way of remaining buoyant. We can’t rely on floating objects like last time, so we need something on our person. Of course, since we’re up against a giant shark, it would be best to not get in or even approach the water.”

“Are you planning to walk around with a float or rubber boat? That’s going to affect your everyday life.”

“I have an idea that might work. Only might though.”

The discount store had most everything we needed, but the atmosphere changed when we approached the area with hardware tools and anti-crime goods. Instead of an area for a happy family, it felt more like a place for muscular men to secure the materials for some secret plan.

“A life jacket?”

Himatsuri-san sounded confused by what I reached for.

“They’ve started selling them like normal to prevent accidents when playing in rivers. Plus, this is Kukyou City. We specialize in disaster prevention.”

The size did not really matter, but it would have been weird to buy children’s ones for a high school boy and college(?) girl. I chose one that fit my body type.

Maxwell displayed a speech bubble on my smartphone screen.

“They work the same as a car’s airbag. Pull on the string and several chemicals mix together to instantly produce nitrogen gas and inflate the balloon.”

“Now we don’t have to walk around with a float or rubber boat. It only takes up the same space as a bento box. And even if we don’t actually wear the life jackets, taking them apart and sticking the balloon portion in our bags should give us buoyancy.”

It would of course be best to wear one under our clothes, but that would stand out when walking around town or attending school. It was all about compromise.

“What are we going to do about a crowbar? We can’t just carry one of those around.”

“Just like lock-picking tools, you can’t just walk around with something used to open locked doors. Unless you’re a professional locksmith, you’ll be arrested.”

I kind of missed Vegas where you could walk around with a multi-tool knife or even a handgun.

Simply checking the tools corner would not help here. We instead visited the personal grooming section where Himatsuri-san and all her brand name attire fit right in.

“Umm. Nail clippers with a nail file?”

Those things would indeed be difficult to use in place of a crowbar. But we needed to change our viewpoint.

“What we’re looking for in a crowbar is the solid metal body and the L-shape that lets us use leverage. But if that’s all we need, we don’t need to risk walking around with one of those. A bridge railing, a sliding window frame, an electronic sign’s frame. Steel parts bent at a right angle are everywhere. We don’t have to worry about breaking things over there, so if we need something, we can just remove the screws and borrow it.”

“I see. But then wouldn’t we want a screwdriver?”

“Just like a lock pick, you can get in trouble for carrying those around without a good reason. Maxwell, will this product work?”

“Sure. The maker’s design document says the stainless steel nail file is made from a single piece of metal with the rubber grip attached afterwards. Remove the grip and the thinner portion below should function as a flathead screwdriver.”

Needless to say, a flathead screwdriver could remove either a flathead or Phillips screw. The size of the screw would also matter, but we wanted a sturdy piece of metal we could use as a crowbar. We wouldn’t need to remove extremely small screws, so we only had to think about middle and large sizes.

“The nail clippers can work as pliers. It’s the same concept.”

“It would be somewhat difficult, but you can likely grab the screw or bolt and turn it with that,” said Maxwell.

It was roundabout, but that was why it functioned as camouflage. I wanted to avoid letting my fear of the glowing ocean make me screw up in reality and have the police or a teacher keep me from acting. Because it might be more than just the shark who was working against us.

“But it looks like we really don’t have a way of defeating that giant shark,” said Himatsuri-san. “I just hope it doesn’t learn and figure out how to respond to each of our methods.”

“About that…”

I was hesitant to speak up because a lot of this was unknown to me as well.

“We assumed we couldn’t defeat the Leviathan because a hunting rifle at close range wouldn’t be enough to break through its thick muscles and fat and because we can’t get our hands on greater firepower here in Japan. That was the assumption.”

“And?”

“But I noticed something during the industrial complex battle yesterday. If we can destroy that glowing ocean with reckless abandon, then can’t we throw out that assumption? They didn’t actually work, but the exploding tanks and collapsing smokestack had to be more destructive than a hunting rifle.”

“Ah.”

“We can’t walk around with a bazooka or drive a tank around. But since the glowing ocean is based on reality, we can use anything found in the real Kukyou City.”

“You mean we might be able to win? Yes, that’s right! We could blow up a tanker truck or break off the top of a mountain transmission tower and send that high-voltage current into the flooded area!!”

“Let’s try one thing at a time. That shark is going to force us there either way, right?”

It would be difficult to blow up a tanker truck or destroy a transmission tower right away. But there were a few simpler methods that would still be fatal to marine life.

I only had so much allowance money, so I had to go with what I could afford.

“Where are you going?” asked Himatsuri-san.

“The appliances section that prioritizes low prices over quality.”

“What are you looking for?”

I had a vision, so I immediately answered her.

“An old model of washing machine.”

Part 3

We didn’t know when the Leviathan would challenge me to today’s round, so we wanted speed.

The buildings and objects in the real Kukyou City would be present in that sunken world.

“All this is pretty heavy once you gather it together…”

It was probably unusual for someone to be aware of its weight.

I set down the sack on the edge of the road and took a break. It was camouflaged among the sandbags meant for frozen roads in the winter, so no one was going to move it.

While that giant shark was frightening, I couldn’t exactly set up a bunch of plastic explosives around the city. The safest option was something entirely useless in reality but dangerous in that demon lord’s ocean.

But that was easier said than done.

The battlefield was the entire city and no one knew where the “today’s exit” goal would be. I might be able to choose the starting point by diving into that blue hell through some kind of water, but I could not rely on guesswork since the route I would have to take depended on the goal’s location.

That meant I had to set up those sacks all across the city.

We used Maxwell’s container yard as a work area. We prepared a giant pile of those sacks, loaded them one by one on my collapsible bike, and distributed them around the city.

Himatsuri-san was wearing a mask and goggles while mass-producing the sacks, so the distribution was my job.

Maxwell used a social media speech bubble to speak from the smartphone I had attached to my collapsible bike’s GPS holder.

“Couldn’t you increase your work efficiency by asking for Miss Ayumi, Miss Erika, and the Class Rep neighbor’s help?”

“That could draw the Leviathan’s attention to them and I’m not getting them registered as participants. Everyone around me is way too kind, so they would probably run headlong into trouble if I told them.”

That also meant I couldn’t ask for help from Itou Helen the Witch or Muramatsu Yukie the Dark Elf. They had extraordinary powers that could not be explained with modern science, but they would have difficulty in a brawl against a 30m shark in a sunken city.

Ayumi and Erika had been helpless against our stepmom, who was Lilith, a true demon lord. And the Leviathan was apparently on the same level as her. This was on a different stage. Being an Archenemy was not enough to ensure someone’s safety here.

“All I’m doing is travel back and forth between the city and the container yard. I can handle that myself. It’s not worth dragging other people into this mess.”

“Sure. If that is your decision. But that does not mean the others will accept it.”

“I’m aware of that. Once this is all over, I’ll apologize for leaving them in the dark.”

Kukyou City had a wide variety of locations: from the coast to the dam in the mountains. Carrying the sacks out one by one and then making a U-turn back to the container yard took hours.

The distribution was far from even and the sun had long since set by the time I had positioned a decent amount of them. It was so late a high schooler would get in trouble for still being at the arcade or karaoke box.

“Warning: Continue any longer and the patrolling police officers will not overlook you. What you are doing is harmless, but they will order the sacks removed if they are discovered. You should avoid any noticeable actions.”

“Understood, Maxwell. We can finish this up tomorrow.”

I called Himatsuri-san and told her it was time to head back home.

“…You’re talking to a young woman waiting alone in a dark container yard, but you’re not being a man and offering to accompany me home? Ohhhh, I see.”

“Oh, hell. Fine then!!”

That gave me my final job for the day. I whipped my exhausted body into motion and followed Maxwell’s navigation to the container yard.

The city was the same as always.

Even this late, groups of boys and girls younger than me were walking through the shopping district. The people entering the train station without paying any attention to their surroundings were likely salarymen with families. Despite the signs stating the local regulation against calling for customers, there was almost always a young man next to the crosswalks wearing an izakaya apron, spinning a menu around on his finger, and somewhat sternly calling out to people. The convenience stores and gyudon restaurants were so unchanged they made me think they would keep running even after the destruction of the human race.

It was late at night, so the date would be changing soon.

…And yet we still hadn’t been attacked. Would it not happen today? Did we have an advantage if we made sure to be careful about water?

If I did not pay attention to the weather forecast, I could be caught off guard by the rain like before.

“Maxwell.”

“Sure.”

“…How did your research go? Y’know, looking for victims of a giant shark.”

“No. I have not made a report because I have not found anything worth reporting. I have gone back ten years in the electronic versions of the local newspaper, but there are no mentions of strange corpses that sound related to this. I am constantly intercepting the radio transmissions from the police and firefighters, but I have found nothing promising. The first reports from the scene cannot be altered, so it does not seem the incidents are merely being suppressed by some kind of pressure.”

“That makes it sound like the victims go missing…”

“Sure. On a national scale, more than 80,000 missing people are reported to the police every year. Although most are voluntary disappearances such as someone skipping town in the night or running away from home, so they are not considered criminal in nature. Thus, simply searching for missing people would not be enough to narrow it down.” Maxwell paused for just a moment. “However, when looking just at Kukyou City, the number of missing persons reports has increased starting a month ago. The Bright Cross was still active back then, so they are not necessarily all due to the Leviathan, but I have found several cases with interesting witness reports.”

“Such as?”

“That the missing person was oddly afraid of water before they went missing. That they were found soaking wet. That they would mysteriously disappear and then reappear somewhere else entirely. And so on.”

…All of those matched Himatsuri-san and my situation.

And that was just what had been reported to the police. There had to have been more people who never told anyone and tried to bear with it themselves.

All of my effort had gone into fighting the Bright Cross.

I hadn’t noticed the SOSs of these people living in the same city as me.

What if?

If I had also been involved in the Leviathan incident back then, would I have been able to defeat that blue bunny girl, Valkyrie Karen? Could I still have rejected the Bright Cross’s ideas by proclaiming I would free all Archenemies from that rule of fear?

“There’s no point in thinking about that…”

Even if the Bright Cross had offered their help in defeating the Leviathan in exchange for allowing the Colosseum to continue, I couldn’t have agreed. That would not have been an option regardless.

Once I arrived in the deserted container yard which looked perfect for some kind of late-night deal, Himatsuri-san noticed me while leaning against Maxwell’s container and doing her nails. She cheerfully waved one of those shiny slender hands.

“So you finally got here, video game generation boy.”

“Please don’t throw me into a category too broad to be meaningful. It’s not like I’ve ever had a chance to play a table arcade game.”

That reminded me that the hot spring inn in the mountains was rumored to still have a legendary alien invasion shooting game along with its ping pong tables and massage chairs, but I had no idea if that was true.

“Well, it doesn’t really matter.”

With a groan of effort that made her sound a bit like an old lady, the cabaret girl sat down on the collapsible bike’s cargo rack. Was she friendly and boyish, elegant and classy, or an old lady? It was hard to tell with her. Instead of solidly straddling the luggage rack like Ayumi, she sat sideways with her legs together. That much matched her apparent wealthy upbringing.

“Driver, take me to Taori-san’s apartment. Wow, my hair is soaked with sweat and the sea breeze. My pride won’t let me work any more!”

“I wasn’t aware freeloaders had any pride.”

Himatsuri-san did not seem to care as she wrapped her slender arms around my waist and clung tightly to my back. She made it look like her sitting in the back was the default.

And she apparently did not care about another aspect of this because I was just a kid: I-I can feel two soft masses on my back! And don’t fidget those delicate-looking hands around below my navel!! H-hwah. What is this sweet smell? It isn’t like the Class Rep’s shampoo or Erika’s perfume. It seems oddly unhealthy and immoral. It must be some kind of luxury makeup or something!!!!!!

She probably only thought of it like holding onto a body pillow or a giant cushion because she did not hesitate to rest her cheek against me and lean her body weight on me.

“Hm? Your heart is already pounding? Are you out of breath already, indoor boy?”

“I have my reasons!”

“Well, you have been pedaling this bike all over the city. Hm, that’s weird. A boy’s sweat isn’t unpleasant at all. I wonder why that is. Sniff, sniff.”

Himatsuri Asami showed no restraint whatsoever. Even if she thought of this on the same level as spotting a stray cat walking along a fence, I wasn’t sure what category to file the memory under.

My mom, Magatsu Taori, lived in a high-rise apartment building nearer to the coastal shopping district than a quiet residential district. It would not take long to pedal the bike there from the harbor block.

Or it shouldn’t have.

But while waiting at the light to cross the pedestrian scramble in front of the train station, I spotted something unpleasant out of the corner of my eye.

“Maxwell.”

“Sure. I have confirmed it with the camera lens.”

A warning message appeared on the smartphone in the GPS holder.

There was someone on the other end of the pedestrian scramble. There were not many people around since it was past 11, but I saw a stubbly man in a gray work jumpsuit with his hat pulled deep over his eyes.

I did not recognize him.

The problem was the heavy-looking object he held in his right hand: a white plastic bucket. And just the bucket would not be so heavy.

Besides, it was odd to be walking around with a liquid-filled bucket without any other janitorial equipment. That would be like taking a test with an eraser but no pencils, mechanical or otherwise.

Himatsuri-san also seemed to notice.

“What is that…? Detergent?”

“Or water.”

The dry sound of the word seemed like it would split my lips.

Water.

The entrance to that death match.

The light was going to change soon. Once it was green, he would be released. It was worth being a little worried, so I grabbed the handlebars again. I considered changing our route, but then I saw something else that was very bad for my heart.

Standing a short distance away was someone who looked like a cabaret girl with stiff hair of a far lower grade than Himatsuri-san. She had a coat that looked synthetic folded over her arm. It was probably meant to cover her exposed skin instead of keep out the cold, but I caught a glimpse of something below it. Was that the muzzle of a water gun? If it had a hand pump, I couldn’t just laugh it off as a children’s toy.

It only had to be enough water to fit our vertical bodies, so a manhole-sized puddle would do it. That meant a bucket or a large water gun were valid weapons.

“Dammit! Maxwell, search for an escape route!!”

We didn’t have time to just sit around. I jerked the handlebars over to forcibly change course and began pedaling away from those two. At the same time, the pedestrian scramble’s light turned green and the stiff-haired cabaret girl tossed aside her cheap coat. And it did not end there. I heard something heavy hit the ground and looked back to see a washbasin’s worth of water fall in the exact spot we had been stopped a moment before. They had dropped it from a window or rooftop!

“Warning: Be on the lookout in all directions. I cannot predict a route. Watch out for assassins lying in wait!!”

“What are these people!?” asked Himatsuri-san. “Are they trying to send us to that shark’s place!?”

“It’s either that or they want to see you with wet and see-through clothes. Which seems more likely to you!?”

It was past 11. The day was nearly over. If it was true we could only be taken into the water once a day, the Leviathan would not want to waste that ticket.

“Who are they!? Why would our fellow humans side with that giant shark!?”

“I don’t know. They might have been threatened in that glowing ocean!”

I pedaled full speed around a nearly circular bus roundabout, but on the way, an employee messing with a hose in front of a family restaurant sprayed water at us and a drunk in a suit chucked his beer can at us. We could not let that hit us or ride over the puddles they created on the road. The more time passed, the farther the minefield would grow.

I swerved in an S-pattern and managed to get past the roundabout and away from the train station.

“Dammit!!”

Then I slammed on the brakes. I used the lever for the front and back wheels and also pressed my feet against the ground.

An old man was flinging water out of a ladle to cover the way ahead, but that wouldn’t be for uchimizu this late at night.

This was far more troublesome than the ones trying to hit us directly. If the road was covered with a puddle too wide to jump across, we would lose our escape route.

I twisted my body around to check and saw a few people clearly running after us.

It was now or never.

“Himatsuri-san, get off!”

I snatched the smartphone from the handlebars, abandoned the collapsible bike, and ran into a nearby alley. Himatsuri-san seemed to be following close behind.

“What do we do? Where do we go!?”

“That’s the thing…”

I heard the sound of rubber soles on the ground up ahead, but we didn’t have time to see who it was. We were surrounded. So we climbed over a short metal door as if for a fence and began climbing the emergency stairs clinging to the building wall. I heard splashing water from below. This was creating a major commotion, but no one would think it was any more than some mischievous people having a water war in the middle of the night. The police weren’t going to bother showing up. And yet our lives really were at risk!

“What do we do? Where do we go? Climbing is only going to leave us cornered at the top!!”

“Yes! We’ll be hit eventually like this. And if they cut off the entire train station block with that uchimizu, then we’re trapped. So we have to change our priorities!”

“?”

“If we know we’re going to be chased by the giant shark in that flooded world, then we need to at least give ourselves a decent starting point.”

I wasn’t proud of this decision. I couldn’t decide whether or not this was the right thing to do. But sitting around wasn’t going to help.

“The glowing ocean is submerged up to about the 5th floor, so we can’t start from a puddle on the ground. We need to least avoid starting on the ground level!”

I felt a powerful tug on my arm, so I pitched forward and came to a stop. I looked back in confusion and saw Himatsuri-san clinging to my left arm like a child. She was pale-faced and shaking her head.

“Himatsuri-san.”

“We can’t do that.”

“Himatsuri-san! We can’t stop here! We can’t escape them even if we turn back now!!”

“We just can’t!! That thing is beyond human understanding. We can’t just assume we’ll be lucky enough to survive again!!”

We had made all sorts of preparations.

We had bought materials at a discount shop, worked in the container yard, and distributed out secret weapon throughout the city.

But that did not mean we would be mentally prepared when the time came. Plus, I wasn’t exactly a survival expert. There was no guarantee our plan would really work, so I understood why Himatsuri-san hesitated to make the running start.

But that girl with her blonde hair in a giant flashy hairdo did not have another plan. And complaining was not going to fix anything here. The gun had been cocked and we had no idea when it would fire!

“Anyway!!”

There was no time to worry about appearances. I somewhat forcefully dragged her to the multi-tenant building’s roof like I was bringing a struggling child to the dentist.

“Ah, ahh, ahhhh…”

She looked like she would collapse the instant I let go of her hand. It did not matter that a younger boy was watching her. She no longer cared.

And I couldn’t blame her.

It didn’t matter if you were an adult or a child. Anyone would be afraid.

Her puppy dog eyes wavered with uncertainty and pleaded me not to abandon her.

They pleaded me not to let go of her hand even on the other side.

“…”

I gave a wordless nod just before I heard the unreliable emergency stairs creak. I turned back to see a man in a gray work jumpsuit climbing them. He held a white plastic bucket. I recognized his stubbly face. It was the man I had first noticed at the pedestrian scramble. Thinking back, he had seemed the most murderous of them all.

I doubted we could escape.

The water would pour down on us and the puddle at our feet would drag us into the demon lord’s ocean. There was no stopping it now.

So…

The thought that came to mind may have been similar to a hopelessly dark joke. But as inappropriate as it might be, these were the words that came to me.

“Himatsuri-san.”

“Wh-what?”

“Let’s bring him with us. It pisses me off to think the guy causing this commotion gets to watch on from a position of safety.”

She looked dumbfounded at first.

But then she laughed.

I was glad because that at least meant she liked my sense of humor.

And as the work jumpsuit man showed some confusion when he sensed the change to the atmosphere, the two of us gave a cry and charged right toward him…

Part 4

I didn’t feel any water this time.

That may have been a first. We were sitting on a multi-tenant rooftop as if we had fallen on our butts. I felt a dull throbbing pain in my hips. It was a stormy night with a widespread blackout that left everything dark. And the flooding beyond the building’s railing emitted a pale blue light that reminded me of glow-in-the-dark paint. …You’ll be fine. Remember when you fought Erika in the simulator? You can find a way through this.

And…

“Rah!!”

Himatsuri-san was collapsed next to me, but she thrust out her long leg to kick something away. It was the work jumpsuit man who we had dragged along with us. But there was something odd about it. He was entirely limp, so the kick sent him rolling along the roof until he came to a stop like an abandoned tricycle collapsed on its side in the park.

I had no time to think too much about it and no obligation to bother with him. I pulled my waterproof smartphone out of my soaked pants and called up the camera function.

“Maxwell, use the zoom. Check the other buildings’ windows. Photograph and analyze the ‘today’s exit’ map!”

“Sure.”

I got up and walked to the railing while the blowing rain pounded on me. The flooding was especially bad this time. I looked down and couldn’t even tell where the roads had been. The taller buildings were sticking up out of the blue torrent and that was the only hint of the original city left.

It was difficult to see the windows of the building we were on, so I pointed the camera lens toward the windows of a building across the floodwaters.

“I have confirmed an identical pattern in every pane of reinforced glass. This is not something created just by the blowing raindrops and gravity. I have confirmed the ‘today’s exit’ text and the arrow. It would take a very twisted point of view to see this as anything other than the same situation as before.”

“Where exactly is it pointing? Link with the map app to check.”

The map’s quality was about the same as one drawn in crayon by a child. And it was zoomed in to only show the two or three nearest intersections. I had to wonder how anyone without this kind of support had ever found the location. You would have to be as familiar with the city’s layout as a taxi driver or newspaper deliverer to know.

But.

“I cannot locate a corresponding location.”

“What?”

“It may be an issue with the precision of the hand-drawn data, but this combination of intersections does not exist within Kukyou City.”

“That’s impossible. That app is really high quality for being free. The offline data should be enough for this. It should even have the entire spider web of private roads in the residential district.”

“No. No matching location exists.”

“Wait a second, Maxwell. Does that mean it can set the goal outside the city!?”

The storm pounded on my body and the world seemed to distort around me. I suddenly felt hopeless. This would mean today’s door could be in an Egyptian pyramid or even a space station!

“I have determined there is an issue with the hand-drawn map. Shall I relax the search conditions?”

“…”

The placement was random. And there was a chance of it being impossible to reach. The unfairness of those rules hit me all over again.

“…No, wait.”

“Yes?”

“The map app does have all the small roads that fill in the gaps of the city, but it just use empty boxes for private land and buildings. It might have private roads that everyone uses and semi public roads jointly funded by several companies like that industrial complex, but it doesn’t have the roads inside amusement parks or malls!”

The only condition was for it to be a door inside the city. If it was the door to a private home’s bath, it would not show up on any map, paper or digital. Did that giant shark want us to go on a treasure hunt!?

“To determine the internal structures of as many buildings as possible, I am searching publicly-released pamphlets and guide maps remaining in the web cache. I have found a matching location.”

“Then it must not be a normal house. Where is it, Maxwell? A department store? The airport?”

“Sure,” came Maxwell’s usual affirmative. We had finally made the first step. This was far better than running around at random. We had a chance at survival.

Or so I thought.

But then Maxwell gave the answer.

“It is the underground mall spreading out from the train station of the harbor sightseeing district’s shopping area.”

……………………………………………………………………………………………………………………………………

What was that supposed to mean?

I looked down at the world visible beyond the metal railing.

I heard the roaring of rushing water.

“But, wait.”

I finally managed to get that much out.

“Everywhere is covered in five stories of water! And we’re supposed to dive down into an underground mall!?”

“Sure. I cannot find any other hits for the geographical conditions. Of course, I only have access to the data remaining in the web cache, so that is not a 100% guarantee. It could also be within the former Bright Cross’s secret facility, but the odds are good it is that location in the station’s underground mall.”

“Then…what? We’re supposed to dive about 15m down in that torrent of water and search through the labyrinthine underground mall for a door that might not even open due to the water pressure!? And all while a submarine-sized shark is chasing us!?”

I could not even count how many deadly barriers were in our way now. And the dangers of that sunken city had to be far greater than what an amateur like me could imagine.

“No.”

But Maxwell had a different view.

“It is possible the underground mall has not been flooded.”

“What?”

“Kukyou City is known as a disaster-prevention city that promotes disaster research, so shelters and rubber boats can be found everywhere here. It is possible the disaster shutters operated correctly and sealed off all the entrances to keep the floodwaters out. And what little water is getting in through the gaps may be quickly pumped back out.”

“…”

That did make sense, but it was still a gamble.

The entirety of the city was flooded by that glowing ocean and there was a largescale blackout. We didn’t have time to scope out the full extent of the damage, but if the backup power was also out, then the shutters and pumps would be useless.

After some thought, I realized we had no other option. Once the giant shark noticed us, it might start tackling the multi-tenant building that was already creaking from the pressure of the water’s current. And we had no idea what would happen if we did not pass through the designated “today’s exit” door. Would a new door be designated once the day ended, was the flow of time different here and the day would never end, or would the door’s orange light vanish, leaving us trapped forever? We could not carelessly boycott the door without knowing that. All we knew was that passing through the “today’s exit” door before we were killed would allow us to live another day.

I sighed and scratched at my hair which had grown annoyingly heavy after soaking up so much of the storm’s rainwater.

“…It’s dangerous, but we have to do it.”

“Sure. And even if the underground mall is safe at the moment, it might only be a matter of time. Its current safety is no guarantee of its safety 5 minutes from now.”

That was right.

I still didn’t get why the Leviathan bothered giving us an exit each time, but if it liked to give its prey a fighting chance, then it was entirely possible it would say we had been given an exit but lost our chance because we were too slow.

“Let’s hurry, Maxwell. You too, Himatsuri-san!”

I shouted over the storm.

And we once more began our death match with a giant shark in the sunken city.

Part 5

I glanced at my smartphone and saw it was 11:30 PM.

The day would be over in half an hour, but in this extreme environment, who could say how many ways there were for us to die in the time it would take to make 10 cup noodles. My knees felt week when I looked down at the roiling water, but I forced myself to remember the simulator as a sort of good luck charm.

“Maxwell, we need to reach the train station first. Search for a route from our current position.”

“Sure.”

Our final destination was the underground mall, but there was no need to dive down all 15m within the surging water. Kukyou City was famous for its disaster prevention and recovery research. It would be safer to break a window on the upper floors, enter the station building there, and work our way down through the giant airtight container.

I linked my smartphone’s GPS with a new map app that provided altitude differences for use with drone flights. The offline data would be more than enough, but anyone would have tilted their head at the shortest route displayed using a red line. It was clearly ignoring the roads. Checking the number of floors in the buildings showed that the route followed buildings of similar heights that were close enough together to jump across with a running start.

And even that was not enough to ensure our safety.

“The wind is so strong. Do we really have to run and jump through this?”

Yes, we were in the middle of a powerful storm of blowing wind. Keeping straight during the running start was difficult enough, the rooftop was slick with rain, and my phone’s backlight was not enough to judge distances well in the blackout. And a single mistake would send us plunging down into the floodwater.

“How about you at least break off your heels?” I suggested.

“A-are you kidding? These are a limited model from Trisme’s Paris Selection and they won’t recover afterwards like the buildings in this glowing ocean will, dammit!!”

She complained but did not hesitate to actually do it, so she did not seem to be the kind of wealthy person who was overextending her finances and on the verge of bankrupting herself with credit card purchases. To her, a brand name item like that was still something that could be thrown out if need be.

…She was really a mysterious person. She seemed to be staying in my mom’s apartment, but what kind of life had she come from originally?

I was wearing athletic shoes, but I had never been the athletic type. Even after preparing as well as I could, a sudden surge of wind could send me right down into the water.

“Notice: I will display the wind direction based on the noise picked up by the mic, so please use that for reference. You will likely fail to make the jump if you attempt it with a complete headwind or within 30 degrees of one.”

“Is that the extra arrow here? It’s spinning around and around like a broken compass.”

“Sure. This is not a normal environment. You are in the middle of a storm.”

The gaps we could and could not cross changed depending on the wind direction, so it did not look like we could take the shortest route. We also could not just stand around forever. I had to remember that we might have to take some wide detours.

And with that…

“Let’s get going.”

“Yes, let’s go.”

The man collapsed on the roof did not matter.

We had to start by getting to the next building.

I rummaged through my pocket and pulled out the nail file I could use as a flathead screwdriver. I used that to remove the metal railing and secure a route for the jump.

…This was a test case. If we failed here and plunged into the water, we could not hope to make it. Luckily, the great height did not make my legs lock up in fear. Was that because my peace-dulled mind did not equate a fall into water as deadly or did the glowing ocean simply not feel real?

Whatever the case, this was the starting line.

We had about 10 meters to make a running start. When I started forward, Himatsuri-san seemed drawn forward alongside me. The crosswind felt like an invisible mass as it hit our upper bodies from below and then we leaped from the edge of the roof.

It was about 3 meters to the adjacent building.

There was no difference in height.

That was not that far, but time seemed to stop as soon as I made the jump. No, had the wind direction changed!? I felt like an invisible wall had slammed into my face and a cold sweat further soaked my already wet body.

But I had made the jump, there was no turning back. I could only stare at the other roof as if in prayer.

Once my body caught up with my mind, it had been flung on top of the neighboring building. That one had not had a railing in the first place. Unable to stay on my feet, I collapsed to the wet rooftop and took deep, almost-choking breaths.

Himatsuri-san actually seemed to have handled it better than me.

“Let’s move on to the next one,” she said. “We can’t just stand around.”

“I know…that. But that headwind…”

“Headwind?”

She looked confused.

Was it possible there had been no headwind and I had just imagined everything slowing down due to fear? I felt like reality and my imagination were blurring together.

I checked the available routes and the constantly-changing wind on the smartphone map and then we made the jump to the next building.

“What is that shark doing?” asked Himatsuri-san with her fancy blonde hair completely flattened by the wind and rain. “I doubt it would just ignore us after going to so much effort to invite us here.”

“…”

I didn’t want to think about it too much, but a possibility did come to mind.

Since Himatsuri-san and I were together, this source of fear was not divided into an individual room for each person. We were all in here together like an online game. That meant there could be people other than us here. If the killer shark was not here, then it was probably with someone else.

It was possible it had gotten a better catch than expected and was having a feast.

“For one thing, was that water attack only targeted at us? If everyone who has succumbed to the giant shark was targeting any of the participants who were being relatively cautious…”

But I did not manage to say any more.

Far in the distance, a giant form parted the water and shot straight up.

The crosswind did not affect it in the slightest. It may have been most like a dolphin jump. But the act appeared so much more sinister when it was done by a shark measuring over 30m long. A dolphin jump took the creature three or four times its body’s length, so at that size, it could reach the roof of a 40-story luxury apartment building!

“Th-the only building I can think of taller than that is a broadcast tower…”

“More importantly, why did it jump?” asked Himatsuri-san. “It wasn’t a performance meant as a greeting, was it?”

That image only brought fear and disgust. It reminded me of the giant fish in the amazon that would jump near the water’s surface to catch flying insects in their mouths.

Then what was this thing eating?

It was not insects. That was for sure. Had someone been jumping from building to building there, just like us?

“D-dammit. Are you kidding me!?”

Had I really come to terms with that idea? Was I only feigning calm after being left hopelessly behind?

Someone had died there.

Shouldn’t my legs be trembling as I collapsed to the rooftop?

“H-hey, what is that thing that looks like a wall? A-a huge wave!?”

“…That’s because the shark bastard fell into the water. Watch out!!”

I didn’t have time to wallow in sentiment.

The two of us clung to the legs of the water supply tank on the roof, but the wave fortunately did not envelop that. I still felt the low vibration below my feet and felt a painful squeezing in my chest.

The very building had been shaken.

Working out the fluid mechanics equations would probably have made me shudder. It was possible the entire building could collapse…

“H-Himatsuri-san!”

“Yes!”

We quickly ran toward the next building. If the Leviathan had eaten the other group just now, it would change course. And it had come to a complete and utter stop within the powerful current. It was clearly aiming our way. Was it coming!?

After we jumped to two more buildings, a powerful destructive sound struck us from behind. The giant shark had finally tackled a building to bring it down. Was it trying to take away our footing to drag us down into the water, or was it trying to get us to jump so it could swallow us whole in midair? We did not have time to worry about the details. We just had to move on to the next building.

The train station was still a bit away.

Would the Leviathan reach us first!?

That was what I thought, but…

“H-hey. Isn’t it acting weird?”

“?”

“That shark looks more like it’s writhing in pain that going on a rampage. Could it be…?”

Was our trap working?

Was that what she was asking?

Part 6

The glowing ocean was based on the real world. So if a traffic light was destroyed in the real world, it would also be destroyed here.

Changes could be carried over. We had taken a simple action when we realized that.

“Whoa, whoa. What is this? Are they all crushed plastic bottles!?”

“Yes. About a container full. Kukyou City isn’t great with anything not related to disasters, so they’re treated as non-burnable trash instead of being recycled. They’re just sent to a landfill, so no one will miss them if we borrow them. I rewrote the trash disposal data to have them sent here instead.”

That said, it had been an awful lot.

The work would have been endless using a household juicer. That was why I had looked for a super-cheap washing machine. I didn’t need a tilted drum or color loss prevention AI. An outdated two-drum one like you would find at the entrance of an old apartment could be bought for less than 10,000 yen if you knew where to look.

From there, we only had to attach a few ruler-like scrap pieces of stainless steel inside the rotating drum. I already had an industrial power source for Maxwell, so as long as I used a transformer to adjust the voltage and amperage to household levels, the motor would turn. I hadn’t even needed to hook it up to a water hose.

“Himatsuri-san, you just keep throwing the plastic bottles in this shredder.”

“Um?”

“I’ve drawn a red line with permanent marker on the inside. Once the powder has reached that line, hit the drain button to send the powder out through the hose and into a sack. And of course don’t stick your arms inside or they’ll be caught in the rotating drum or handmade blades.”

“What exactly is this supposed to make?”

“Microplastics, the enemy of almost all marine life.”

The word could be seen all over TV and the internet like it was some kind of fad, but I was willing to use whatever I could.

“We fill some sacks up with them and then place those around the city. Nothing will happen here in reality, but in that flooded hell, they’ll be caught in the current and scatter the microplastics everywhere. That should do definite damage to the shark’s heart and gills.”

A shark of that size would be able to swallow a human or a car, but entering through the esophagus and through the gills were too different things.

“But if we leave them on the side of the road, won’t they be picked up as illegally dumped trash?”

“We just have to put them somewhere that they won’t look out of place… I know. We can camouflage them with the sandbags for frozen roads.”

We had set our trap.

We had spent a full day tearing up the plastic bottles, stuffing them in bags, and placing them around where no one would notice them.

We had not managed to cover all of Kukyou City, but that did not matter when the shark was approaching our home base. With knowledge of the terrain and the power of a simulator, it was possible to predict what areas would have more microplastics and which courses would be especially thick with them. Maxwell’s test calculations said some areas would have 1200 times the microplastics of the natural sea. This weapon was truly limited to the glowing ocean.

Now we just had to continue fleeing while luring the shark into the damaging areas.

We don’t have teeth as big as yours, but we prepared an invisible weapon. Now, breathe it in and feel the pain.

Part 7

Each time the Leviathan thrashed around, its rows of giant teeth tore through the corner of a building rooftop like it was tofu and its tail fin smashed an office building’s windows along with the wall around them.

It was in pain.

It was clearly suffering.

“But it’s not enough! Not even this can keep it from moving!?”

Himatsuri-san shouted that while we jumped from rooftop to rooftop.

There had been fears of negative effects from inhaling microplastics. It was supposed to be something like pneumoconiosis in humans. This did definite damage, but was it not as immediate as a knife or bullet!?

And of course, the monster had even more strength than normal while thrashing around in pain. It could no longer aim carefully, but each impact had even more explosive force behind it. That was how it seemed anyway.

“Himatsuri-san!”

“Eh? What? That doesn’t lead to the station!!”

She sounded confused when she saw which direction I pointed and started running in. But she seemed to follow me in the end.

I heard what sounded like the air bursting behind us. Was it a roar or a collapsing building?

The giant shark pursued us and destroyed even reinforced concrete in its direct approach.

“Do we have any chance left!? What do we do now!?”

“In all likelihood, we’re screwed!” I glanced back over my shoulder. “It can knock down buildings if it tries, but that doesn’t mean it can do so effortlessly.”

It may have been like how tearing a single piece of paper was easy but 100 sheets of paper could stop a bullet.

“Keep in mind how big it is. If we lure it into a cramped area with concentrated buildings and narrow roads, it might get stuck and won’t be able to move.”

At 30m long, it was the size of a small submarine. When I thought about it rationally, there were surprisingly few areas of the city it could freely swim through.

The way it had destroyed the reinforced concrete buildings as it approached had been frightening, but didn’t that also mean it wasn’t able to avoid them and kept brushing up against them?

“But won’t it thrash about and knock over all the buildings! It’s gotta be really mad!”

“We just have to get into the station and head underground before that happens. The microplastics aren’t a devastating blow, but it means a lot to know it can’t just ignore them. We can bring that information back with us and use it for next time!”

To avoid the Leviathan trapped in an alley, I chose a wide detour while taking wind direction into account and jumping to buildings with a similar height. I had no idea how long this would last, but it did not seem like that monster was about to tackle the station and squash it flat.

We were on a multi-tenant building that stood 5 or 6 stories tall and the train station was 13 stories tall thanks to the observation platform restaurant at the top. The heights did not match up, so it would be difficult to enter through the roof. However…

“The trash has piled up here.”

Some kind of decorative thread was strung across and the rubble and scrap metal flowing in the water had gotten tangled in it. In one spot, the piled-up garbage reached a width of several meters. The floodwater seemed to pass by below it, so it was almost like a floating island or bridge.

“If we cross that, we might be able to break a window and get inside.”

“Are you serious!? If it sinks the instant we step on it, it’ll dump us straight in the water!”

To be safe, I used the nail file as a screwdriver to remove a home TV antenna from the roof and used it to test my weight on the path ahead before actually stepping on it. After confirming it was solid, we crossed.

The window seemed to be made of reinforced glass for high-rise buildings, so it did not budge when I threw the metal antenna rod at it.

“Please strike the window with the tip of the nail clippers’ grip portion. That should more efficiently create a crack.”

I followed Maxwell’s advice and stabbed the window like I was using an ice pick. A spider web of cracks ran through it, so I stabbed at another spot. It was like a game. Once several spider webs overlapped the same spot from three or four different directions, the window fell apart.

“Hurry, hurry.”

“I am!”

This method was apparently meant to open a small hole near the window’s inner lock to pass your index finger through, so it took some doing to create a hole large enough for someone to pass through.

Even so, I managed to create an entrance and we crawled inside the train station.

“Bwah!”

Indoors, we had steady footing and no blowing rain. That should have been a vast improvement, but we actually trembled now that we had this normal environment. We had remembered just how drenched we were.

I checked my smartphone and saw that about 5 minutes had passed. I wasn’t sure if I should ask “that much?” or “that’s all?” Either way, that giant shark was not going to sit idly by. It had to have nearly regained its freedom after smashing up those more-than-half-submerged multi-tenant buildings.

I swung my smartphone’s backlight from right to left and searched for the stairs down.

“We need to get going. Who knows when we’ll run across further trouble.”

“R-right. Uuh, it’s kind of cold…”

Himatsuri-san held her own shoulders and shivered as we advance through the dark station’s department store. My smartphone’s backlight was all we had to rely on. The elevators would not be running during this blackout, so we had to find an escalator or emergency stairway.

“Is that an escalator?”

We headed the way Himatsuri-san pointed and descended the stopped escalator. It felt like an unsteady flight of stairs. But it only brought us down one floor. We had to search out another route to arrive underground.

“Why are you going that way?”

“There’s an emergency exit sign. It’s hard to tell with the power out, though.”

We walked down a long straight corridor with one wall covered by reinforced glass windows filled with that blue light that looked like glow-in-the-dark paint.

Just then, something slammed against the outside of a submerged window.

“!?”

“!!”

We rapidly backed into the opposite wall. And it was more than just the loud noise that scared us.

The fifth floor which was barely above the water and we were a floor below that. It was completely flooded outside, so why was a middle-aged man plastered against the window!? I hadn’t seen this even in the simulator!

“H-hurry! We have to save him…!!”

Himatsuri-san pleaded me while her hips gave out and she panicked. She was right, but something seemed horribly off about this to me.

To us, it was like viewing a tank in an aquarium, but that glowing blue water was rushing by. How was that man clinging so firmly to glass which had nothing to grab onto?

And just as I wondered that, I saw something.

Something like sticky, slug-like bugs wriggled out of the man’s mouth and nose.

“Uuh.”

This time.

This time, the scene before my eyes truly surpassed my psychological limits.

“Waaahh!?”

I fell back onto my butt. Himatsuri-san stopped begging to help him and instead froze in place with eyes wide.

What were those?

What was going on!?

Trembling, I glanced down at my smartphone where Maxwell explained in a social media speech bubble.

“They appear to be a sea leeches, but they look much more sinister than any in the encyclopedia.”

“Sea leeches?”

“Without even referencing the remora, sharks are a treasure trove of parasites. From the adult forms to the eggs, they are exposed to danger in every stage of life.”

We watched as the window filled up. It was like watching leaves plaster themselves against a wet window during a windy storm. Three, four, ten, twenty…no, even more! As far as the eye could see, the windows were filled with people plastered to them!?

Was this the answer?

The giant shark itself swam through the open sea. But for smaller areas it could not reach, it used its leeches and remoras to chase down and force out its prey.

They worked cooperatively.

The injuries received in the glowing ocean remained in the real world. In that case, were the Leviathan’s pawns not simply being threatened? Were they being controlled by the parasites filling their bodies!?

This was an Archenemy.

Those immortal beings were seen as sources of infection and reproduction.

We had thought the only real risk was in the glowing ocean. We had thought the giant shark could not reach us once we escaped this place, no matter how violent it might be.

But we were wrong.

People were dragged onto the battlefield, infected by parasites, and then controlled in reality. We had no way of knowing who was being controlled! And we couldn’t just physically block them out!

“Himatsuri-san, we need to hurry! I don’t know what this is about, but this place has got to be dangerous. That reinforced glass isn’t going to last forever!”

We had to run. I didn’t want to be torn to pieces by the giant shark’s teeth, but having the depths of my head infected by parasites that sucked all my body’s blood sounded even worse.

The legends said the Leviathan was a source of food that could feed all the people in the world. I had thought a 30m body didn’t seem like enough, but now I was afraid the real food source was all the parasites it could produce endlessly!

The ominous creaking of the reinforced glass rushed us onward as we relied on the unlit emergency exit signs to run down the passageway.

We soon found the emergency stairs.

There was an indoor stairwell completely surrounded by walls next to the elevator. The storm and current would mean nothing there.

“Hurry up!”

“I’m going as fast as I can!!”

I was afraid of my wet shoes slipping, but I grabbed the railing and ran down the stairs from the fourth floor.

With all the metal shutters closed in the underground mall, it was just like a labyrinth. There was no light, so the remaining battery for my smartphone’s backlight was the same as our lifespan.

The shutters covered the glass windows, so we didn’t even have the sloppily-drawn map.

“Maxwell, where is the goal door?”

“Sure. Turn right at the second intersection. The shutter is closed, but there is a human-sized metal door next to it. That is the ‘today’s exit’ door.”

That was when I heard a great roar from overhead. Then a low tremor shook the ceiling. And it did not stop. In fact, it was getting louder!?

“One of the windows must have broken. The aboveground area was already flooded outside, so it’s pouring in like a dam releasing its water!!”

Had the infected people plastered to the windows caused this? If so, the leeches and other creepy parasites coming from their mouths and noses would be mixed in with the flash flood. If we were caught in that, it was all over.

“A-anyway, to the exit!! There’s no turning back now!!”

That went without saying. We would not be safe without climbing more than 5 stories, so fleeing upwards was not an option now. And once the underground mall flooded, the water pressure would probably keep us from opening the “today’s exit” door.

So we had to run for it.

We had to turn right at the second intersection up ahead and pass through that door to reality!!

“!?”

“!?”

We ran as fast as we could. Behind us, we heard a sound just like waves crashing against rock. We could not even look back. We were supposed to turn at the second intersection, but Himatsuri-san started turning at the first. I had to grab her arm and correct her course before we turned at the proper place. My shoes skidded across the floor as I did. My entire throat was dry. Unable to stop myself, I slammed into the opposite wall, somehow managed to avoid falling over, and started running again.

The stores with long French-looking names all had their shutters down. I had no idea what kind of stores they had been, but that didn’t matter. What mattered was the small employee door next to the shutter in question.

That door was glowing orange.

And it said “today’s exit”.

“Make it.”

I could not bring myself to check on the torrent of water behind us. If I saw it, it would probably bind my soul with fear and I wouldn’t be able to run any further. So I faced forward as I ran full speed and held my hand as far forward as I could.

“Make it!!”

I grabbed the knob and more tackled the door than opened it. That produced a loud noise, but that was all. Only then did I realize I had to pull the door not push. I dragged my aching body along as I actually opened the metal door and slipped through. I collapsed through to the other side.

And…

And…

And…

Part 8

“Pant! Pant! Urp…!?”

I couldn’t believe that was my own breathing.

Himatsuri-san and I were soaked and lying on the cold floor together. She stared fearfully back at the puny metal door.

But it was not destroyed and no dirty seawater flowed out.

Today’s battle was over.

We were no longer in the glowing ocean. It was the usual calm and peaceful Kukyou City.

“Ha…ha ha.”

The giant shark could use those leech-like parasites. We had no way of knowing how far the infected had spread into the real world or how to physically locate them. The situation had grown more serious, but we still had smiles of survival on our faces.

“Ah ha ha ha! Ha ha ha ha ha ha ha!!”

If it was before midnight, the last train would not have left yet and there might still be some station employees left even if the store was closed. We couldn’t explain what we were doing inside a store after it had closed, so we should have been calmer. We knew that, but we couldn’t help ourselves. If we could not tell ourselves this had been a happy day, then we would break right here. We were being attacked by bizarre infected people and a ridiculously-large shark had picked a fight with us, so if we viewed things in a negative light, we would be too overwhelmed to move.

So we continued laughing.

It was like how loneliness was amplified more than 100-fold when working alone at night. We could not stop this ritual until the dark feeling in our chests was entirely gone.

How long did that take?

Tears had welled up in our eyes by the time we finally calmed down.

“Let’s head home.”

“Yes…”

With that quick exchange, we followed Maxwell’s instructions through the shutter-filled underground mall and headed aboveground. I couldn’t even think about what kind of security there might be or how we were slipping past it. I was so exhausted I started wishing Maxwell had a body to princess carry me with. This was not the first time, but I was reminded just how exhausting it was to fight for your life. It was on another level entirely from a soccer or basketball game in gym class. The weariness seemed to remove the very core of your mind.

I was tired. I wanted to sleep. Like a log.

Himatsuri-san and I arrived aboveground and saw a group of drunken salarymen and college students.

“…I wonder how many of them have a head full of leeches.”

“I don’t want to think about it. Hey, want to grab a bite to eat? Taori-san probably has a meal waiting for us, so she would be upset if we ate a full meal, but some fries should be fine, right?”

“You can eat fries this late?”

“We’ll split a serving. That should be fine, right? And my heart is even more worn down than my body. I want to recover by enjoying that extremely simple flavor…”

I did understand how she felt. It was the same as wanting to rush to a karaoke box the instant you were freed from the tension of a major exam.

At any rate, we had our survival ticket for the day. The microplastics had had some effect and we could use that experience to do even better next time. With another day, we could accomplish anything.

With that in mind, Himatsuri-san and I walked to a burger shop in a cramped multi-tenant building. We were exhausted, but we were still on our guard. We avoided any puddles and we kept our distance from any passersby since they could always be controlled by the leeches.

But while we were waiting for the light to change, a large dump truck passed by right in front of us. Its tires drove through a puddle and splashed water our way.

Normally, we might have just complained about it for a moment.

But we currently could not even shout out in surprise.

“…”

“…”

We were soaking wet.

There was a new puddle at our feet.

And I glanced down at my smartphone. The clock said 00:03.

The day known as “yesterday” had ended and the day known as “today” had begun.

Which meant the Leviathan had already recharged…

“A-are you kidd-…!?”

I didn’t even have time to complain.

We were instantly dragged back into the demon lord’s ocean.

[Self Record] Report on Parasites [Leviathan’s Record]

Shockingly, more than 80% of the lifeforms confirmed on the planet are reliant on some other lifeform to survive. And humans are no exception. It is obvious if you think about it, but humans cannot survive on their own. From food to clothing, we are blessed by other lifeforms. Do not forget that even petroleum was originally animal protein.

You think that is mere wordplay?

Then what are parasites from a scientific perspective? They are lifeforms that attach to another lifeform and absorb nutrients without supporting or killing it. Although there are some that will bring about the death of their host.

Snails and mantises are well-known for being hosts to parasites that control them, but that is not actually all that rare. Even humans have countless gut bacteria inside their bodies. And have you ever changed what you thought you would eat based on how your stomach was feeling?

All lifeforms are controlled by something.

And the biggest slaves of all are those who are oblivious to it and stubbornly deny the possibility.

Chapter 3

Part 1

Back-to-back rounds.

We had to play two rounds back-to-back.

“Cough.”

I couldn’t breathe.

I couldn’t see either. My eyes, nose, and mouth stung like they were being rubbed with coarse salt. By the time I realized I had been thrown into the seawater, my body was tugged by an incredible force.

“Cough, cough! Ghwah!?”

I flailed my arms and legs wildly, but it was no use. I eventually realized that multiple currents were intertwining like living creatures and I was trapped between them.

I reached into my bag and pulled a thin cord.

Two pillow-sized balloons inflated. I had obtained them by taking apart a cheap life jacket. I clung to them as I made my way to the surface.

I had been caught at ground level this time and the water was about 5 floors’ worth. That was 15 meters. Would I make it? I had to! I prayed and clenched my teeth.

“Bwah!?”

My mouth finally breached the surface. I felt dizzy, but I wasn’t sure if it was simply oxygen deprivation or if the water pressure had caused a minor case of decompression sickness.

I did not at all feel like I was saved.

After all, this dark sea was full of who-knows-how-many people infected with parasites. We still did not know how the infections occurred, but I couldn’t be optimistic. I had to assume the water was infected.

And…

“Himatsuri-san?”

The current swept me along as I clung to the balloons and glanced around.

Himatsuri-san, where are you!? Dammit!!”

There was no response as I called for her.

The surging water glowed with a sticky bluish light much like glow-in-the-dark paint. I was tossed around on the surface but somehow managed to grab onto an electronic sign sticking out from the side of a building.

Where was she?

Dammit, there was no way I could overlook that bright blonde hair and champagne-colored dress!!

What would I do?

Stay put, or dive down to search for her?

“…I can’t.”

I shook my head. There was zero visibility in that muddy water, so searching through it in the middle of the night without a proper light would be suicide. I had no way of staying in one spot and I had no oxygen tank.

But there was something I could do.

I clenched my teeth and tightened my grip on the sign. Over and over, like some kind of magic words, I told myself it would be okay while thinking back to that fight in the simulator. A small sign was attached at each floor, creating a vertical row of signs saying Harumi’s Yakiniku, Marukawa Detective Agency, and so on. I used them as a ladder to reach the roof. I had to climb about three floors. I endured the blowing rain and somehow made it to the top.

I aimed my smartphone’s lens around the roof.

“Maxwell, find something I can use as a rope. And a float!”

“Sure. In the home garden space, I see a vinyl rope and a fertilizer bottle. If the latter is empty, it should supply buoyancy.”

Every second counted, so I pulled out the rope, tied one end to the bottle, leaned over the roof’s railing, and stared into the surging water.

“Is Himatsuri-san there?”

“I do not see her.”

The flow of water was swift and complex. Had she already been swept far away?

That might not be so bad if she had managed to escape to safety on her own.

But just as I thought that…

The water split before my eyes and an enormous mass leaped out toward me.

“Waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhhh!?”

I screamed and fell on my ass.

It was the giant shark.

The Leviathan.

It could pull this off just by using its ridiculous mass of muscles as a spring. Tripping was the only reason I dodged the jagged rows of teeth that passed right above my head. The 30m beast flew in an arc that passed just above the roof, bit right through the water tank, and dropped down the other side.

That was way too close!

Is it attacking directly instead of using its parasites!?

“Warning!”

“I know!!”

And I could not have the shark kill me here. I had to find Himatsuri-san and pull her out of the water.

I heard the water parting once more. That giant form may have been turning around before building up speed for another leap.

I did not have the firepower to directly defeat the Leviathan. That left only one thing to do.

“Dammit!!”

I got up and ran with all my might. I used all my weight to tackle the door into the building and broke the lock. Just as I collapsed inside, a violent wind roared behind me and I heard more and more metal being destroyed. The Leviathan must have charged in and crushed the industrial air conditioner unit that was the size of a small storeroom.

My legs locked up with fear, but I forced myself to run down the stairs.

“What are you going to do?” asked Maxwell.

“Divert its attention elsewhere.”

Fortunately, I had seen a certain name on the signs I used to climb up the building.

“Harumi’s Yakiniku. Is this it!?”

On the 6th floor of the multi-tenant building, my body scraped along the walls of a narrow hallway and I ran into the empty restaurant. I ignored the customer floor full of grill-equipped tables and entered the kitchen. I pulled out a hunk of beef from a giant silver fridge and opened the lid to the kitchen garbage bucket.

“Sharks are sensitive to the scent of blood, aren’t they? I hope that isn’t one of those common beliefs that isn’t actually true.”

I had to try anything I could. I wouldn’t be able to search for Himatsuri-san with the Leviathan locked onto me.

I headed to the window in the kitchen. As the rain blew onto it, the usual messy hand-drawn map covered the glass: today’s exit.

That was our one and only means of survival since we had no way of fighting, but I didn’t have time to compare it with my map app at the moment.

“Maxwell. I’ll take a photo, so you analyze it and check it against the map app. If that doesn’t work, use the maps from pamphlets and sites you find in the web cache like before.”

“Sure.”

I grabbed the fire extinguisher installed by the floor and smashed the window with the thick metal container. The blowing wind and rain rushed in and I was hit by the shards of glass I had just created.

“Uehp! Dammit!!”

But I couldn’t worry about that. I took the beef, the fat which couldn’t be sold, the garbage, and the juices and blood that oozed from damaged meat and I dumped them all out into the water.

If that drew the Leviathan’s attention, I could get away from it. Once I had my freedom, I could resume my search for Himatsuri-san.

Please.

Please fall for it!!

Just then, the wall to the side was blown away.

It was…the Leviathan.

Despite the bait, it tackled into the multi-tenant building and destroyed the wall. The kitchen was not all that large, but I was still blown from one end to the other.

“Gbah! Ggehah, ubwah!!”

I crashed into the tile wall, fell to the floor, and writhed around in pain. I couldn’t breathe… It felt like an invisible hand was pressing on the center of my chest, so I couldn’t draw in any air!!

…But I was still lucky.

I had not been hit by the giant shark’s teeth. If it had bit me, my torso would have been split in two. I had only been hit by a piece of the building that had broken off when the shark broke through the wall.

“…”

That thing was more than 30m long. Only its nose could fit inside the cramped kitchen, but I was still hit by some kind of invisible pressure that threatened to crush me.

And I heard an odd sound of moving air. At first, I thought it was the Leviathan breathing, but it couldn’t be. It was a fish. I did not produce air bubbles when breathing.

Which meant…

“Warning: the gas line has been ruptured. If the pipe itself is damaged during a power outage, the gas will leak out.”

“!!”

I did not have time to follow along with the smartphone text any further. I practically rolled through the half-collapsed and rain-filled kitchen to reach the customer area. The giant shark moved its nose to follow along and I heard some kind of small snapping sound. It had likely crushed some kind of metal.

It happened just as I moved out of the kitchen.

I was rolling along the floor, but a powerful blow hit me in the back and sent me flying through the air. It was a gas explosion. There was heat, noise, light, and a shockwave, but it was the sound that came from my neck that frightened me most of all!!

“Gbwah!?”

I couldn’t brace for impact and rolled across the floor. I only stopped after breaking through the thin partition between tables.

I looked back toward the kitchen and saw fire spewing from the rectangular entrance. But that wouldn’t be enough to kill the Leviathan. It had charged toward us while explosive flames erupted all around it in the industrial complex.

“It will be coming soon,” said Maxwell. “Prepare yourself.”

“Why didn’t it go for the bait!? I thought a shark’s nose was better than its eyes or ears!”

For one thing, the seawater was not perfectly transparent, so marine lifeforms could not focus too much on sight. Or so I thought. Had that trivia quiz show been making things up!?

“I have not confirmed any of the details, but I could make an educated guess here.”

“That’s fine. You are a simulator, after all.”

“In addition to blood, sharks use the specialized ampullae of Lorenzini on the sides of their head to read the faint electric currents in the seawater.”

“Electric currents?”

“Sure. A living being such as yourself has bioelectricity, so a shark would be able to distinguish you from some frozen meat.”

So it only ate live bait. This lord of the ocean was quite the gourmet. But that did make sense. I still didn’t understand the logic behind the glowing ocean, but it was made to be a convenient feeding ground for the Leviathan. That was why the city was entirely flooded, so there also had to be a reason for the blackout.

In that case…

“Where would the employees be a lot…? I know, the register counter.”

“Could you tell what you intend to do?”

I climbed over the counter as I replied.

“If we send electricity into the water, we can take out its prized nose. It’s sensitive enough to detect the faint current from a human body, so it doesn’t even have to be as powerful as a stun gun.”

“No. The power is out, so I doubt you could find such a power source.”

“Have you forgotten, Maxwell?” I rummaged through the things below the register. “This is Kukyou City, home of disaster prevention. There’s always at least a flashlight around.”

Once I switched it on, I slammed the lightbulb’s protective cover against the corner of the counter.

With an explosive noise, the customer area’s wall was broken through from outside and the giant shark crashed through the opposite wall and escaped into the ocean. The tables and chairs were a complete mess. If I had not moved to the register on one end, I would have been killed instantly.

And that open hole was actually convenient.

The flashlight was broken and the wiring exposed, so I chucked it through the hole in the wall and into the water.

The giant shark veered from its path as it made a U-turn and tried to charge back this way. It swam diagonally and broke through the neighboring building instead.

I shrank back and whispered into my smartphone.

“Let’s get going. This won’t last forever.”

The Leviathan was an Archenemy with a basic structure very much like a shark’s, but it was not actually a shark. For example, a vampire might look like a bat, but they were tougher and cleverer than a mere bat. Similarly, the Leviathan might have sensory organs a real shark did not.

To find Himatsuri-san, I made my way to the roof where I would have a better view. Meanwhile, Maxwell used a social media speech bubble to speak.

“User, I have found a region of the map app that matches the window map.”

“Where’s the exit this time?” I asked as the rain blew against me on the roof.

“Shinryoku Inn in the mountains.”

“…Wait. What did you say?”

“There is no doubting it. The door marked ‘today’s exit’ is there.”

…That was too far away.

I glanced down at the roaring blue water and desperately gathered strength in my legs as they threatened to give out.

First of all, traveling from the coast to the mountains required crossing the entire city. But there was only so far you could go while jumping from building to building. It was possible in the dense areas like the shopping district, but the residential areas filled with more separated houses would be entirely flooded. I could not travel far just using roofs.

But would I have to do it anyway?

No matter how unreasonable it was, death was the only option if I stopped here.

“In that case…”

I looked around the roof that had been torn apart by the giant shark’s repeated attacks and I spotted a metal box. I would have been screwed if this was a normal regional city, but this was Kukyou City, home of disaster prevention.

Any commercial facility that gathered a certain number of people would have one of these: a motor-equipped rubber boat that inflated like an airbag at the push of a button.

I had used one during the fight between Erika and Ayumi in the simulation. Even though entering the water had been close to suicide, so I had wanted to avoid it if possible.

I removed the large clasp in the metal box.

“Maxwell, simulate the flow of water. Calculate out where Himatsuri-san would have been taken from our starting point.”

“Sure.”

With a “poof!”, the rubber boat took shape just like in a crash test scene on a car commercial.

I tossed the inflated rubber boat in the water and climbed in myself. It would be carried by the current even without the motor running. My only complaint was the lack of brakes.

“Based on the speed of the water and the passage of time, the most likely location is by the trees of the train station plaza 400 meters ahead.”

“She really was swept away…!”

I used the motor which doubled as a rudder to steer the boat through the current. A great mass seemed to split the water’s surface behind me. That squeezed at my heart, but there was no turning back now.

What about Himatsuri-san?

Where was she?

Where the hell was she!?

My panic threatened to make me overlook her. I swung my smartphone’s backlight left and right before aiming it forward again.

I saw what looked like golden fabric tangled around the top of a tree sticking up above the water.

It was her dress.

“Himatsuri-san!!”

I shouted her name, but she did not seem to have the energy to respond. I controlled the motorboat and somehow managed to get close to the treetop. I made sure the boat wasn’t swept away while also making sure I didn’t injure her with the propeller and I pulled half-conscious Himatsuri-san into the rubber boat.

“Pwah! Pant, pant…”

In her drenched dress, Himatsuri-san lay sprawled out in the boat, gasping for breath. The cabaret girl style of dress left her thighs exposed up to the base, but she did not seem in any state of mind to care.

And this was no time to be focusing intently on human observation.

This time, the water split apart directly behind us.

“Dammit! Maxwell, navigate us!!”

“Sure. But there is an overwhelming difference in speed between the disaster-relief rubber boat and the Leviathan. The rubber boat can only move at 100kph, but you cannot escape the Leviathan by moving in a straight line. It is not a mere shark.”

“I know…that!!”

But we had no hope if we abandoned the boat either. If we were going to cross the flooded city to reach the mountains, we needed the boat to follow a course across the water. So we could not abandon it if we were to reach the “today’s exit” door.

“Maxwell, analyze the images from the smartphone lens! Locate any power sources other than the home power, like battery-powered products!!”

“Sure. The first on the list would be this smartphone and rubber boat.”

That could have been interpreted as sarcasm or a joke, but unfortunately, the simulator was entirely serious.

Yes.

This was not the only boat. They were stored all around the city, so we could always use a different one. The problem was that we had no time to come to a stop and I couldn’t think of any projectiles capable of destroying a distant box. But even so…

“Maxwell, mark any targets on the footage!”

“Sure. I will display them based on their proximity to the Leviathan’s predicted path.”

I viewed the scenery through my smartphone and saw a glowing outline around a rubber boat storage box. That just meant I had to steer the boat so the area representing the shark’s course aligned with the box.

It could maintain perfect balance and charge straight forward even in such a powerful current.

It tore through the half-submerged rooftop and its belly turned the boat storage box into scrap metal. Once the damaged battery fell in the water, the giant shark began veering unnaturally off course once more.

The effects did not last long, but they were there all the same. Sending electricity into the seawater apparently messed with its sensory organs. It didn’t really matter if this was true of all sharks or if it was unique to the Leviathan.

“If we could predict how it would veer off course, we could probably get it to skewer itself on a piece of rebar sticking out. Its own ridiculous strength could probably break through its muscles.”

Himatsuri-san must have been exhausted and pissed off because her thoughts had shifted toward attack. But we could not hope for that much. Getting back alive came first. We could use the information we received here to put together a plan once we got back. We did not have to challenge this 30m shark in an all-or-nothing gamble. We knew our odds were poor and we only had one life to work with.

We left the shopping district and cut across the residential district. The entire area was flooded and we could not see any tall obstacles that stuck up above the water’s surface. I knew my house and the Class Rep’s house had to be below that water, but it did not seem real.

“This is bad,” said Himatsuri-san. “We can’t slow down the shark here!!”

The boat batteries were waterproof, so the flooding would not be enough for their power to leak out. Plus, we could not destroy the boxes deep underwater while traveling along the surface.

And if we could not divert the giant shark’s path, it would catch up and swallow us whole. The intense current would not slow it down.

I estimated we had about 30 seconds.

Maxwell did not have an answer, so what were we supposed to do in this fruitless current? Where were we supposed to go!?

“Himatsuri-san, do you have a phone!?”

“Eh? Well, I have my smartphone…”

“You’ve backed up what’s on it, right?”

“Hey, wait! I need that address book and the photo I took with that girl!!”

Before she could fight back, I snatched the smartphone from her hand, prepared the nail file I used as a screwdriver, stabbed it into the center of the screen to split open the LCD, and tossed it into the water.

The approaching shark veered off target again. The Leviathan’s diagonal path took it just barely past us and we felt the same powerful wind as when a dump truck drove by.

But survival was a win.

We weren’t as fast as the shark, but the boat was bouncing along the choppy waves at more than 100kph. We quickly made it to the other side of the quiet residential district.

We would next find ourselves at the mountains.

Tall conifer trees poked their heads up above the water. I skillfully weaved left and right so the shark would collide with them and we finally reached the slope that rose up from the water.

“Himatsuri-san!”

“You owe me for that smartphone!!”

We held hands like friends and dove inside a narrow hand-dug tunnel.

The giant shark made a jump directly behind us.

We heard a roar like a head-on collision between a tractor-trailer and a bus. I flipped over, felt my heart pounding, and looked back to see the giant shark’s mouth covering the entrance to the tunnel.

The large teeth snapped shut a few times, but they could not reach us. Unlike the hollow buildings, the tunnel was contained solidly in the mountain slope.

After some resistance, the Leviathan pulled back.

“…”

“…”

Himatsuri-san was collapsed next to me and we exchanged a glance, but we could not exactly take a peek outside of the entrance to see what was happening. If the shark made another jump, it was all over.

“For now…let’s go further in.”

“Yes.”

The tunnel itself was a portion of the path up the mountain, so it ascended. Once we exited the tunnel, the water would be far below us and the giant shark would have a harder time targeting us. …Although that was not a guarantee of safety when it could perform a dolphin jump several times the length of its 30m body.

We hesitantly left the other end of the tunnel.

It was still pouring rain.

But there was no sign of that giant shark. Except for a fin that looked like a giant boulder as it parted the water’s surface far below and moved off into the distance.

“Did it give up…? Has it decided to focus on another target on this field?”

“I’m not sure. Maxwell, do you know what’s in that direction?”

“Your search conditions are too vague and have received a great many hits, but the greatest risk among them would be the Kukyou Dam.”

“…The dam?”

“If it destroys that to raise the water level, this area could flood as well.”

I felt dizzy.

My face had to be as pale as Himatsuri-san’s.

“Maxwell, display the route to the inn where the ‘today’s exit’ door is! We need to get out of here while we still can!!”

“Sure.”

“Wait…why!?” asked Himatsuri-san. “It couldn’t destroy this hand-dug tunnel, so tackling that thick dam isn’t going to-…”

“A dam’s strength isn’t the same everywhere. If it pinpoint targets the water gates, the one point of destruction could spread to the entire dam.”

“Due to the great pressure, it only need be a single crack,” explained Maxwell. “It might be best to think of it like a passenger plane falling apart in flight due to the smallest hole.”

Whatever the case, this was not good. We followed Maxwell’s instructions to move off the asphalt mountain road and walk along an animal trail created by parting the underbrush. It was a pitch-black route right out of a test of courage. If the situation hadn’t called for it, I would have avoided walking down it even with Maxwell’s guidance.

And there was something up ahead.

I heard something stepping on the underbrush, sensed a presence, and saw a silhouette between the trees.

“…Who is it?”

We were not the only ones dragged into this demon lord’s ocean. We had no way of determining whether there was a single “today’s exit” door or multiple, but if the other participants were following the map in the windows and mirrors to find the goal, then it was possible a large number of people would be gathered at the same inn.

But something wasn’t right.

It was odd.

I immediately turned off the smartphone backlight. Himatsuri-san’s face remained tense and she did not run over to whoever it was. In fact, her wet hand grabbed at my coat. Her fingertips were trembling.

The human silhouette’s head was wobbling unsteadily and their shoulders were at mismatched heights as the blowing rain hit them.

Something dripped from their face. At first I thought it was raindrops or possibly tears or snot running down their face.

But it was not.

They were fat, balled-up leeches.

They pried open the eyelids, descended from the nostrils, and dropped dropped dropped dropped…

“Gh, ahhh!?”

I cried out and moved back, but the sole of my shoe slipped and my back hit the tree trunk behind me.

They must have noticed that because their head clearly turned to face us.

…Damn!

“A parasite host!? Are they stationed near the goal to stop us!?”

The path no longer mattered. I grabbed Himatsuri-san’s hand and ran out into the full undergrowth.

The infected people were used to enter areas the Leviathan’s giant body could not and drive out its prey. They were like hunting dogs. They had handled narrow passageways and the insides of buildings, but it seemed they also covered the elevated mountains.

So if we just let them chase us around, we would be pushed back to the flooded area.

Plus, I heard a deep roar in the distance.

“Eek! Wh-what?”

Himatsuri-san cowered down and jumped.

The giant shark seemed to have begun its attack on the dam. Even if both locations were in the mountains, the fact that we could hear it meant those attacks were more powerful than civil engineering explosives. I doubted just one or two hits was going to break it, but with no way of stopping it, it was only a matter of time. It would eventually collapse, so we had to reach the exit at the inn before that happened. The infected hiding in the forest were a threat, but if we held back out of fear, the water level would rise and this area would flood.

“Maxwell, do leeches have any kind of weaknesses?”

“They are generally weak to fire and will apparently let go of your skin if you burn them with a lighter…but that is true of most any lifeform. It is unusual for fire exposure to make something more active.”

Besides, we could not light much of a fire in this pouring rain. And even if we did have plenty of firepower, we would probably start a largescale forest fire. Burning down the demon lord’s ocean did not really matter, but we had to avoid killing ourselves with the fire and smoke we started.

“But if you need something…”

“What is it, Maxwell?”

“Sure. As they were attached to a shark, they are likely a variety of sea leech. In that case, wouldn’t they be unfamiliar with this mountain forest environment with so many plants and trees?”

“Be more specific.”

“Sure. Just like a papercut, wouldn’t they be shredding their body’s soft surface when they move around here?”

“…”

I looked down at the ground covered in underbrush.

…Were those plants their weakness? If so, would they grow weaker as time passed, unlike in the sunken city? It did make sense since the marine Leviathan was forcibly using what was available to it.

“But we can’t just wait until the spiked floor damage takes them out…”

Still, it could help that they were not at their best. If they disliked the forest and the mountain, we probably didn’t have to worry about the leeches leaving the infected people’s bodies and crawling along the ground.

We gathered a long stick from the ground and poked along ahead of us as we continued on. I didn’t want to use the stick for a fight since we didn’t know how powerful the infected people’s bodies were. I was just checking to make sure one of them wasn’t hiding behind a tree or below the underbrush.

Another loud roar rang out.

It sounded like a bell counting down to destruction.

We continued on while occasionally hiding behind cover to let a human silhouette move past.

“…That’s it.”

We walked between the trees and parted the tall underbrush to finally reach an open area. There was a wooden mansion on the mountain slope that had been intentionally made in an older style.

There were a few figures wandering around the parking lot and front entrance, but they did not seem very intelligent. I had asked Maxwell for course corrects a few times as we left the original route, but they did not seem to react much to the sound or light.

These were not the Leviathan’s primary means of attack. It was a lot like attacking with the lice in your hair. These infected people were clearly inferior to a vampire like Erika or a zombie like Ayumi.

“…It’s dangerous, but I guess we have to go for it. Himatsuri-san.”

“I know. The forest behind us has the infected wandering through it too, so it isn’t any less dangerous.”

We did not have the guts to approach the inn gate from the front.

We stayed low and walked quickly along the wall, but there was an unsteady infected person at the back entrance too. They could apparently be given simple instructions and stand guard. We turned back while making sure we were not spotted.

But they were only standing guard at the entrance points.

The wall between those points was about 2 meters tall.

Himatsuri-san could climb over if I gave her a boost from below.

“Nnnnnhh…!!”

I was a little worried about her pulling me up, but that worked too.

Once we were on the inn grounds, the hurdle was a lot lower. We did not know the total number of infected, but the inn was divided into many rooms, which gave it as many windows as a school or hospital. They could not post a guard at all of them, so we had plenty of ways in.

We located a window without an infected person looking out it and quietly approached. It was probably locked, but that just meant we had to break it without making much noise. I used the method Maxwell had taught me before. I stabbed the nail file screwdriver into the glass near the internal lock. I did it again a few centimeters away. After creating a small triangular shard, I removed it, stuck my finger through, and opened the internal lock. It was a burglar’s method, so I felt my heart pounding even though I wasn’t up to no good.

The dark Japanese-style building had deep shadows inside. It was impossible to tell where the infected might be wandering.

“…Maxwell, where is the ‘today’s exit’ door?”

“Sure. It is the door to the detached room bordering the courtyard.”

That was quite a noticeable spot. I wasn’t even sure we had needed to enter the main building, but cutting through it had to be shorter than circling around it.

Once inside, there were a lot more blind spots. The long stick was an absolute necessity. I would open a door, stick the stick through, and only poke my head through once there was no reaction.

We climbed out through a hallway window and entered the courtyard.

We spotted the detached room while the blowing rain hit us. Something like a small hut was located in the center of a Japanese garden. It felt more like a space for drinking tea than a guest room. It was connected back to the main building by narrow bridges across several ponds.

We ignored that path and rushed over to the detached room while remaining low to the ground.

That was when an explosive roar arrived from the distance. It was likely the giant shark’s attack on the dam. But this one sounded different – wetter. My instincts told me that was bad news. The water gate must have been smashed enough for the dam to break.

“Himatsuri-san!!”

“Yes!!”

We could not worry about appearances. We could not predict how long it would take for the water to reach this level. All the noise caused windows to open or shatter as several infected people crawled out of the main building. They were not just on the first floor. They dropped down from the second and third floors as well. If we were caught it was all over, so we ran full speed toward the detached building.

today’s exit.

We saw the glowing orange light of that door. A deluge of water and so many hands pursued us as we tackled that wood-paneled sliding door…

Part 2

“Bwah!!”

Even back in reality, it took me a while to get up. Earlier, I probably would have been trembling with the joy of survival, but I didn’t feel that this time. It was lucky there was no one around this detached room, but I was too out of it to even think about that.

I could tell.

I had pushed my body too far. Unlike the previous one-time rounds, the charge timing had put us through two back-to-back. That meant we were safe for almost a full 24 hours now, but we could not relax. The extra burden from this time had left our bodies so worn out we were unlikely to recover in time.

I checked my smartphone and saw it was still 12:50.

Not even an hour had passed.

Each second felt way too long!!

“We need to…get home,” said Himatsuri-san as she stirred on the tatami mats. “I lost my…smartphone…so I can’t call. Taori-san is going to be worried…”

…I was impressed that her normal timetable was still in effect. If there was a time-limited sale, she might have headed out while soaking wet.

But her comment set my gears in motion again. No matter how I felt, the hands of the clock would cruelly continue to turn. They would not stop or turn back for my convenience. That was what her words told me.

“Let’s get home…”

But where was home for me?

My stepmom’s house or my mom’s apartment? I was in an awkward state in which I didn’t know where to go.

“…Yes, I need to get home.”

I was like a walking corpse. I still didn’t know where I would go as we followed Maxwell’s instructions to slip past security and crawl out of the inn’s grounds. Like this, I could hardly laugh at the people with parasites filling their head.

Sometimes you feel nostalgia for TV footage of a rural area you had never visited. The nonexistent idea of “home” in my head may have been something like that.

And once we left the inn’s grounds, we were in the mountain. Dragging our drenched bodies down the winding mountain path was going to wear us out even more. Curse that Leviathan. Do its attacks never end?

“The infected might be returning to reality too. We need to be careful in the darkness.”

“R-right.”

Luckily, we were not attacked by any more infected along the mountain road lit by the occasional streetlight. We were passed by some brightly-lit cars that were blasting music, but the drivers must not have wanted to mess with a boy and a girl soaked with seawater despite being in the mountains. The frustrated delinquents racing along the mountain road left us alone.

After more than an hour of building up lactic acid in our thighs, we finally reached the bottom of the mountain. It was just before 2, so the trains were no longer running. It was not a good time for a student to be wandering around the city.

“Maxwell, gather the current locations of any patrolling police and place them on the map. I want a path around them.”

“Sure. I will also access the servers of the appropriate educational institutions and include the movements of any patrolling teachers.”

“…You two can do anything, can’t you?”

Which “home” would I return to?

I agonized over it for a while, but I ended up dragging myself to my mom. I went to Magatsu Taori’s apartment. It had a lot to do with Himatsuri-san accompanying me. If I had been alone, I might have chosen neither and curled up in the container yard instead. These were the entirely passive thoughts of a spoiled child. Running away from home was supposed to bring about independence and self-sufficiency, but I had only increased my dependency.

“Oh? Why are you coming back so wet lately? But I suppose there’s nothing to worry about if you were with Asami-chan.”

My mom’s eyes opened wide, but she did not ask too many questions. She was kind…or I think that was why. Maybe she was scared too. Our relationship was extremely unstable, so she may have been trying to avoid any unnecessary conflict.

I took a shower after Himatsuri-san and changed into the pajamas that had been prepared for me. Then I sat and thought in one of the guest rooms.

The microplastics had showed some effect.

The giant shark could control people using parasites. The controlled people would appear in the glowing ocean and in reality.

With a battery or some other source of electricity, we could temporarily divert the shark’s aim.

…That was all we had learned. The one about electricity was especially important. If dry cell batteries from a convenience store were enough, we could stock up on extra lives for a few hundred yen. Best of all, we could carry them around in the real city without gathering attention, unless we had a truly excessive amount.

But this was a shark-like Archenemy, not an actual shark. Its intelligence could be equal to or greater than a human’s. It could always learn from and overcome a method we had already used, so we could not rely on this too much. But that was no reason to abandon it altogether.

“…Either way, I can think about this more tomorrow.”

Even if it was technically already “tomorrow”.

I knew I had risked my life to earn this time, but I pathetically found that I could not move once I got in bed. My nerves were worked up, but my body was exhausted.

It looked like this was as far as I was going to get…

Part 3

“Senpai.”

After school, I had agreed to meet someone in front of the school.

We had finished today’s match just after midnight, so we had a full day to work with. And I had of course been spending that time working.

I was meeting with a small girl with naturally wavy blonde hair cut to shoulder length. She was Itou Helen, an underclassman from school.

She was an Archenemy. A Circe Witch.

This cute underclassman was the new queen of the Colosseum and she could use animal-transformation potions. To be blunt, a witch like her seemed like she would stand a better chance against a giant shark than my vampire older sister or zombie little sister.

…I didn’t want to get anyone else involved, but I was just that desperate at this point.

“You said we would be visiting the aquarium, didn’t you?”

“Yes. I made an appointment via smartphone during class, so the caretaker will give us some specialist knowledge.”

About sharks, obviously.

“But if it’s too specialist, I might not be able to keep up, so I wanted someone who could dumb it down for me.”

“No. I can provide any information you might need, user.”

“Maxwell, you can only give me the information I have you search for. For better or for worse, it’s like peering in the mirror. I can’t find a direction I hadn’t considered already.”

Himatsuri-san was not an option for a different reason. She was as much a layman as me and having someone else tilt their head along with me would not help. That was why Itou Helen made for the best “interpreter”. She could speak with a biology expert and also talk on the level of a high schooler.

My small underclassman placed a hand over her mouth and giggled.

“What’s so funny?”

“Oh, nothing. I was just thinking how you two haven’t changed at all.”

I wasn’t sure what that meant.

But anyway.

Our destination was the harbor sightseeing district’s shopping area that had been so useful to me lately. Since so much seawater had to be brought in and out, it was probably easier to build an aquarium on the coast.

It looked like a combination of several giant cubes with the walls and roofs bubbling, so it made me think of some kind of modern art. They must have wanted to be a date destination for older couples because the restaurants inside mainly served alcoholic beverages and had a lot of fancy-looking Western names. The nearby zoo was meant for families and pushed a lot of character goods, so the government office was probably compartmentalizing them.

Their peak hours were at night, so the lady behind the acrylic panel at the ticket counter looked bored.

“I’m Amatsu who called in an appointment,” I said to her.

“Yes, yes.”

It was Itou Helen next to me who tilted her head quizzically.

“Um, Senpai? Do we not have to buy tickets?”

“The caretaker lecture is probably charged differently. I doubt it’s going to be cheaper than normal, though.”

A middle-aged man in a work jumpsuit walked out a bit later and we entered through the aquarium’s main entrance.

“I am Tanabe.”

“Oh, um, I’m Amatsu. This is Itou.”

I had already explained what I was interested in over the phone. Itou Helen looked disappointed as we walked right past the jellyfish and squid tanks, but we were only here for the sharks today. I grabbed her hand and had her hurry on past.

“Ah.”

She gave a quiet cry, but then she hung her head and said nothing more. Her ears looked a little red, but we had to keep going.

“Oh?”

“?”

Then a girl called out to us. She was a gloomy-looking girl with long, glossy black hair. Not even her cheerful hoodie and hot pants could rid of her of the gloominess surrounding her. But who was she?

“I was hoping for more of a reaction than that. I’m Kuroyama Hinoki the Mermaid. You remember me, don’t you?”

“That mermaid who appeared on a national broadcast with only her hair to cover her nudity is wearing normal clothing!?”

“…I see you were focused on exactly the wrong things. So what are you doing here?”

I was also curious what the mermaid was doing here, but she probably longed for the company of the marine life from time to time. Just as a vampire like Erika tended to gather bat goods. And how a zombie like Ayumi loved meat and would decorate her smartphone case strap with small manga meat and fried chicken toys.

I explained the situation.

“A shark Archenemy? That sounds interesting.”

“You can follow along if you want, but I can’t afford anyone other than myself and Itou-san.”

“Don’t just assume I need your help,” she said bluntly.

Speaking of Itou Helen, she had fallen silent and was squeezing my hand. Ow, ow! This really hurts! Was she always this strong? Is it because she’s an Archenemy!?

Tanabe-san did not seem to mind the extra person tagging along. Explaining something to two people was the same as explaining it to one. It made me question why we had to pay more for the extra person, though.

“You wanted to know about sharks, correct?”

“Y-yes. Specifically, the fierce ones like the great whites.”

“Then we should visit the tank in the back, not the one out front.” Tanabe-san smiled. “An aquarium’s back area is quite large. More water is stored out of sight of the guests than in the tanks they can see.”

I didn’t know exactly how the aquarium worked, but there was probably a lot of behind-the-scenes work. You had to do more than just feed the fish every day. In addition to purifying and filtering the water, the tanks had to be cleaned, the fish had to be checked for disease, and arrangements for spawning and birthing had to be made. And clean seawater was necessary for all of it.

I wasn’t really sure how they kept the fish in the tanks from fighting and eating each other, so I decided to let him explain everything.

The caretaker led us through a staff-only door and the passageway grew a lot narrower and plainer. The floor was a bit damp too.

“They don’t look it, but sharks are actually quite cowardly.”

“Cowardly?”

“That is why they actively work to eliminate any kind of threat they see.”

That made sense.

It reminded me of a poorly-trained dog that barked at anything and everything.

“On the other hand, they can be oblivious to things they do not deem a threat. That is why sharks are known as a treasure trove of parasites like remoras and sea leeches. Of course, in the long term, they will rub their bodies against rocks to remove them.”

“So…would they just ignore a drowning baby?”

If so, we might be able to avoid the shark’s focus by disguising as something powerless.

“It’s hard to say. As a sea creature, the very act of a human swimming is an unknown to them, so they would probably fear it and attack. And they would also attack if they mistook the baby for their prey.”

Unsurprisingly, it was not that simple.

When I thought about it, I realized a 30m shark would already see us as powerless.

There was something else I wanted to ask:

“As an aquarium worker, you might not like this next question.”

“I do not mind.”

“How would you defeat a big shark like that? Since you have them in the aquarium, you must have a way of safely defeating them and transporting them without killing them.”

“Yes. It is also possible to cultivate them from eggs, but a net is used to capture them. If they struggle too much, they will apparently be knocked out with an electric shock from an electrode on the end of a harpoon. Electricity travels through the ocean quite well, so it does not have to be millions of volts like a stun gun.”

Electricity again.

The power outage in the glowing ocean felt even more unfortunate. Of course, we could also get ourselves electrocuted and that world was created for the Leviathan’s convenience in the first place

“The effect of the shock would be relative to the shark’s size. So, um…”

“Think of it like a 30m great white.”

“They generally only grow to 7 or 8 meters at the largest. At that size, you might need a direct hit from a real lightning strike to knock it out.”

That was another possibility crossed off the list.

…Or was it?

There was a constant blowing storm in that blue hell. I didn’t remember seeing any lightning, but could I find a way?

Just like I had created an artificial hurricane that spun in the wrong direction in Las Vegas.

“And using a net to cut off its escape would be difficult at that size. The relationship between size and muscle strength is not simple proportional one. It increases at a quadratic rate, so it would just capsize the fishing boat.”

I agreed with him there. That thing could smash right through a smaller building.

…But could we get a net tangled around its body? It had no arms or legs, so it would have difficulty getting it off. Even if a single net didn’t accomplish much, we might be able to obstruct its movements if we got enough of them caught around its tail fin or dorsal fin.

What else did I need to ask about?

“I’ve heard that sharks detect an animal’s electricity and attack that.”

“Yes. As I said, electricity passes through the ocean quite well. As I’m sure you know if you have seen any video footage of the deep ocean, the water is not perfectly clear and it gets dark below a certain depth. So sight is not the main focus when hunting in the ocean.”

Tanabe-san continued walking down the passageway.

“That said, they also use the scent of blood. Expert opinions are split when it comes to the bioelectricity, so it is the basis of a lot of speculation and legends.”

“Related to electricity, you mean? Like, um, being able to fire electricity from their nose?”

“Ah ha ha. I haven’t heard any that go that far. But I wonder… All living creatures have their own electricity, so if a shark used its sharp senses to monitor the bioelectricity escaping its body, it might be able to adjust the minute movements of its muscles to emit a specific pulse. But it would not be like a stun gun. More like a pulse or electric signal.”

“…”

But wait.

A specific, ordered pulse too weak to cause an electric shock.

Emitting a specific signal using the electricity that all life forms had.

Could it be?

But wasn’t that too far-fetched?

“A dive device…”

“?”

Itou Helen tilted her head next to me, but I didn’t have enough specifics to explain.

But what if there was a way to take a signal similar to those in your nerves and transmit it through water or moisture?

Then wouldn’t that extraordinarily-large Leviathan function as a virtual reality facility equipped with an ultra-powerful broadcast tower and supercomputer?

Of course, if that was all it was, I could not explain why the entrance and exit were in different locations or why injuries suffered in that glowing ocean remained in reality.

“B-by the way, where are we…going?”

Unlike when she spoke to me, the friend who had fought through the Colosseum with her, Itou Helen sounded somewhat shy when speaking to Tanabe-san. She seemed to be hiding behind me a little.

“Well, I thought I could provide a more detailed explanation while we viewed the real thing.”

I thought he meant he would show us a great white shark.

But when he opened the metal door, I found something entirely unexpected awaiting us.

It was a 30m shark.

The Leviathan itself was floating calmly inside a special-sized tank.

Part 4

“Sh-…”

I thought my heart stopped when I saw it.

That thing would be able to break right through the pressure-resistant glass.

“Shit!!”

I cursed and faced Tanabe-san in his work jumpsuit. I heard a wet sound as something soft oozed out of his eyes and mouth. Itou Helen and Kuroyama Hinoki screamed when they saw it.

The Leviathan spread its infection using the parasites attached to its body. And they existed in the real world, not just the glowing ocean.

…I had known that, but dammit!!

If the pulse using the shark’s unique sensory organ was used to interfere with people’s brains and send us into a virtual world like with a dive device, then the giant shark that acted as a broadcast tower had to exist in the real world. It wouldn’t just exist on the battlefield!

“Itou-san! Kuroyama-sa-…!!”

I tried to tell the girls to run away, but then something happened.

“Wait, boy. I mean you no harm.”

I could not move.

Not a finger.

Breathing, blinking, and other actions that did not require conscious thought continued, but that was all. It was like I had been turned into a statue!

…It could interfere with our brains.

Was the deep voice I had heard part of that…!?

“Like it or not, I am one of the seven deadly sins. A simple trick like this should not surprise you.”

“…”

“I will allow you to speak.”

“Bwah!? And I’m supposed to believe you? I’m supposed to trust you unconditionally while you could kill us at any time!?”

“I would prefer to not restrain you like this, but when communicating with this method, the binding of your physical body is an unavoidable side effect.”

It was sending electrical signals directly into my brain instead of using words or writing. I felt a squeezing in my chest when I realized I had no idea what kind of chemical changes were occurring in my head.

“And the ability to kill you at any time is also unavoidable. I have no weapons or armor. Simply appearing before you allows me to kill you. That is all this is, so do not read too much into it.”

“Then what about Tanabe-san? Or the other infected people in the city!? Are you going to claim that was unavoidable too!?”

“I am saying I would like to reconcile our differences of opinion about such matters.”

The Leviathan apparently had no way of forming facial expressions, but there was a hint of pity in the voice that sounded directly in my head.

It’s looking down on me!? Dammit!!

“Besides, why would I place myself in this tank for no reason? This is on the coast. Sending the pulse out from the beach would be little different.”

“…”

Tanabe-san was…not moving.

Was he frozen just like us? Along with the parasites coming from his eyes and nose?

“I abandoned the vast ocean in the hopes of showing my intent to ‘disarm’ myself and create a venue for conversation, child of Lilith.”

“What for…?”

“To correct your mistaken assumptions,” said the Leviathan. “Didn’t you find it odd? If I had created that lost sea to attack humans, why would I create a ‘today’s exit’ every time? And no matter how much human cleverness they used, did you really think puny humans could defeat a shark after being swallowed up by seawater?”

“…”

“It is true I have the power to separate people from reality. As I am doing now. But the means alone are not enough to prove someone is the culprit. If someone was murdered with a kitchen knife, you cannot punish every household that has a knife in their kitchen.”

“Wait…” With my body frozen, I could not even gulp. “What does that mean? What are you trying to say?”

“I have only constructed an exit from that lost sea and chased after the people there so as many as possible would escape. You could say I am performing a cyber attack on the virtual space constructed by the game master so I could create an unintended secret exit.”

It almost seemed to be imitating my voice as it explained.

“In other words, I am not the one who created that lost sea or the one forcing you to suffer there. There is someone else. Can you please understand that?”

Part 5

I couldn’t believe it.

I still couldn’t believe it, but what the Leviathan said made sense.

For one thing, I hadn’t known why the Leviathan was after us. Since it was connected to envy of the seven deadly sins, we had speculated it might be trying to attack me over my connection to my stepmom, the demon lord of sloth, but that had honestly been a weak guess.

I still hadn’t found a good reason for it.

So did that meant the Leviathan simply didn’t have a reason to fight us?

“I…no, we have no interest in what Lilith is doing. Including that Absolute Noah plan.”

“Why not? That’s the ticket to escape the Calamity which will affect 7 billion people.”

“Those 7 billion only live on the limited land of this planet. We live in the depths of the ocean, so the Calamity on the surface is of no concern to us. Even if an ice age begins and all land is buried in ice and snow, we will have plenty of light and heat near the submarine volcanos.”

…That was a good point.

“Although it does seem that Lilith’s group would be concerned by the possibility of someone surviving without their ark. They probably think the infection will remain.”

I did not know what exactly the Calamity was, but even if it was a plague spreading across the land or a giant meteor crashing down, the dark world several thousand meters underwater might not be affected.

Humans simply could not survive there.

“You said ‘we’ just now, didn’t you?”

“As a demon lord, I ruled over many of the marine Archenemies. Including the mermaids like her.”

Kuroyama Hinoki did not respond to the Leviathan’s words because she was frozen in place. She had to be panicking on the inside.

“We originally banded together to protect ourselves from the out-of-control Bright Cross working for Lilith. But it did not develop into a largescale conflict because humans generally do not interfere in our habitat.”

The Bright Cross had already been destroyed, so the Leviathan’s organization should have lost its reason to be.

“Yes, with the Bright Cross’s destruction, we should have found peace and been able to disband. Should have.”

“?”

“It was not just the Bright Cross that confused its methods for its objective. Some of us refused to disband and began to wander in search of an enemy that allowed them to continue fighting. And the convenient victims they found were Lilith and those around her, since she led Absolute Noah, the organization the Bright Cross had worked for. You are Lilith’s child and have been given a ticket to the ark, so you were an especially attractive target to them.”

A battle to protect their home.

That alone sounded nice enough, but if what the Leviathan said was true, they were more like a pack of mad dogs focusing on a nonexistent threat.

“Their attacks are affecting all of Kukyou City and I imagine that is because Absolute Noah’s roots run that deep in this city, but it likely also comes from them holding a hostile view of the residents who are unwittingly protecting Lilith.”

“…They? Who are they?”

“Are you ready to believe me now, child of Lilith?”

“I’ll decide that for myself. Besides, if you’re completely innocent, what do you have to say about the parasites infecting Tanabe-san and those other people?”

“Let me ask you something instead: Have you ever actually seen those parasites detach from my body? They are not limited to sharks. Marine life is much more merciless and fierce than you think. When a drowned body washes up on the beach, it is swarmed by a frightening umber of lobsters, crabs, and other creatures. And I believe I told you it was a portion of our marine Archenemy group that has refused to disband and is searching for a reason to continue fighting.”

…Was the giant shark trying to say it was not involved with the parasites?

To be honest, this did not erase all of my suspicions about the Leviathan. Even if this was true, the Leviathan itself could be part of the group searching for another enemy.

I had to be extremely cautious.

And that meant I needed as much information as possible.

“Let’s say all this is true. Then whose reins slipped from your fingers?”

“Ah, so we have finally reached that question.”

Its voice sounded like someone after the train was stopped by an accident and it took more than an hour to reach a store that should have taken only 10 minutes.

And the Leviathan gave the answer.

“Do you know what a Siren is?”

…

That was an ocean spirit from Greek mythology. Just like the Mermaid and Lorelei, they were beautiful women who led sailors astray with their song to sink the ships and drown the people. But they did not have a fish tail for legs. If anything, they had beautiful feathers and were bird-like, I think?

“From the look on your face, I take it you are somewhat familiar with them.”

“They’re bird creatures and the origin of the general word ‘siren’, right?”

“Good enough,” said the Leviathan. “Yes, they are ocean Archenemies, but their nature is closer to that of birds. Thus they are one of us, but they may not be able to ignore the fate of the small bit of the world outside the ocean.”

That reminded me of the story about bats not being able to become land animals or birds.

“…Archenemies that lead you astray with their song, huh?”

I moved just my eyes to glance over at Kuroyama Hinoki.

She was a Mermaid Archenemy, just like you would find in a picture book, but she lacked the power to drag so many people into a glowing ocean. Was every variety different? They appeared similar to us humans, but they were completely different.

“I didn’t realize Sirens had anything to do with parasites.”

“She is at the center of this breakaway group, but she is not acting alone. She has surrounded herself with Remoras.”

“Remoras? Aren’t they just parasites?”

“I suppose I was hoping for too much there. They are not listed in any set mythology, after all.” I thought I heard a mocking note to the Leviathan’s voice. “They are an Archenemy described in an encyclopedia written by a self-styled academic named Pliny. They are a marine lifeform the size of a small fish with suckers on their back. But once they attach to the bottom of the hull, they will bring even the greatest warship to a stop. And they cause strange and wild hallucinations.”

Suckers and hallucinations.

That really did seem to fit the conditions for the culprit.

“An action needs more than just the means. A motive is also necessary. And while the Remoras interact with sailors by attaching to the hulls of ships, they still remain in the water. On that front, it is not surprising to find the flying Siren has a greater motive and attachment to the land-based human world.”

“Got any ideas there?”

“We were Archenemies who banded together against the Bright Cross. We did not ask each other too many questions. But since they have broken away, they must have their reasons.”

“Then what about Tanabe-san…?”

“I am being contained here using some academic research that has yet to be released to the public. The Siren’s group must have detected that and taken control of the caretaker to deter my actions. All I can do is keep him from acting, not resolve the fundamental problem.”

I see.

Setting aside whether or not it was true, I felt like I had gotten as much information as I could from the Leviathan. And with that in mind…

“So what do you want me to do? Since their big boss has bothered to show up and give me this input, I can only assume you want to guide me toward something as your pawn.”

“Their former big boss, you mean. I am no more than an Archenemy now. That group is a thing of the past. It has been from the moment you took down the Bright Cross.”

“…Do you resent me for that too? For bringing chaos to the world?”

“Not at all. It is true the elimination of the Bright Cross took away our group’s purpose for existence. It was sad vacating that fortress in which we shared both good times and bad, but that was a new beginning. I think we need to shake free of the past and continue forward. Come to think of it, I never thanked you. Thank you, child of Lilith. Thank you for having a heart capable of feeling anger for us Archenemies.”

…What I did wasn’t that great.

That comment rose in my throat, but I managed to swallow it back down. I couldn’t spit on the fact that I had saved Itou Helen and Kuroyama Hinoki.

“So this Siren has no intention of leaving the pyramid structure of your opposition group?”

“More than that, you could say they have nailed up the fortress’s gate with boards, cut off all contact, and are wandering around in search of an external enemy they can claim is threatening our internal order.”

“Then you didn’t create that…?”

“I am merely interfering in the space the Siren created for the Remoras.”

So the unseen Siren had created a VR space and the Leviathan was using a cyber attack to embed a backdoor in it?

“They must be made to realize that our group’s time is at an end. That is what I want.”

I really didn’t have a choice.

Whether it was the Leviathan or this Siren behind it, I would lose my safe zone once this day was over and I could be dragged into that glowing ocean by a puddle at any time.

I could determine the truth of the matter then.

“The next time we meet in that glowing ocean, I might run away from you,” I said.

“That is fine by me. As long as your lives are saved as a result.”

Part 6

There was a souvenir shop by the aquarium exit, so I looked around it with my cute underclassman and the person who stripped when she got serious.

Itou Helen seemed to have grown to like jellyfish because she was testing the small, medium, and large jellyfish body pillows to see which one was most huggable. And even though a Mermaid like Kuroyama Hinoki would count as a type of fish, she was watching the sample footage from a dolphin video disk.

Perhaps due to the alarm clocks and penlights they sold, there was a section selling dry cell batteries.

Batteries.

Those cheap extra lives could throw off the giant shark Leviathan’s aim.

“…”

I grabbed a three-pack hanging from the display by a thin stainless steel rod and I debated the issue while toying with it in my fingers.

Since I was debating whether or not to buy them, was I beginning to believe that giant shark on some level?

That it meant no harm.

That the true culprit was a Siren.

…Calm down.

I had only heard one side of the issue. What if this Siren really did exist and she started placing all the blame on the Leviathan? I was worn out from the two rounds in a row and I doubted I could do that again. And next time, the enemy would have learned, making things even harder to survive. If the Leviathan was lying about everything and I made no preparations today, I might never return from that glowing ocean.

And yet…

I hesitated.

I hesitated to purchase the batteries I could use against the Leviathan.

“Senpai?”

I heard Itou Helen’s voice from the side. She had apparently settled on the medium-sized jellyfish pillow. She held the round thing between her arms so it hid her mouth and she gave me an upturned glance.

“It sounds like you’re in a lot of trouble again.”

“Yeah.”

“If there’s anything I can do, um, you can come to me with anything…”

“Me too.”

I heard a short shriek as Kuroyama Hinoki the Mermaid hugged my underclassman from behind. See, it’s just like I said. Itou Helen’s eyes opened wide, her shoulders shrank down, and she froze in place.

“To be blunt, can you even bring us along for this trouble?”

“…”

When the black-haired Mermaid asked her question, the Witch recovered and gave me a somewhat hopeful look. Yes, this was exactly what I had expected them to say. Because I had gotten involved in their trouble to save them, they felt bad that they could not do the same for me.

I was thankful.

But I shook my head.

“Sorry, but I’m not the one who gets to decide who’s invited. I can explain what happened, but taking you along would probably be difficult.”

“I see,” said Kuroyama Hinoki while disappointedly letting go of Itou Helen’s head. “But if there’s any other way we can support you.”

“Sure, I’ll tell you if there is.”

I wasn’t heartless enough to say their feelings were enough. It was true the fight to the death happened in the demon lord’s ocean, but we had to worry about how we were viewed in reality as we made our preparations. Just like when I had acted as Itou Helen’s second, there were ways to help without actually stepping up onto the stage.

I parted ways with Itou Helen and Kuroyama Hinoki and I went back to my mom’s high-rise apartment building.

…Went back.

Since I was avoiding thinking of it as “returning home”, I really was an ungrateful person. And I would still accept her help, so I was shameless too. I was like a cat that showed up every day and got food there but insisted I was a stray since I didn’t wear a collar.

“Satori-chan, do you want dinner?”

“Yes.”

I realized my mom was always there waiting for me, but how did she pay for the apartment? She didn’t seem to go work at any kind of office.

Later that night on the balcony where my mom wasn’t watching, I had that question answered by Himatsuri-san who also ate dinner there as a freeloader.

“She seems to have some source of income beyond the alimony she’s paid each month. And since it was enough to buy a family apartment even though she lives alone, she must have a lot saved up.”

…That had to be what she had been paid to cooperate with clinical trials at the Peace Committee Convalescent Hospital. She had thoroughly modified her body to fight Archenemies, so her body had to be full of patents, patents, and more patents.

“Alimony from the divorce, huh?”

“Hm?”

“It’s just that I ran away from home, but I’m stilled tied back to it like that. The world seems so small when I think about how the food I just ate was paid for by the very home I left.”

“You can never escape your parents’ influence. No matter how old we are, we can’t change the fact that we were born from our mother’s body and we can’t deny the obligation we owe them for raising us. Although that can be stifling at times.”

…That was true.

I could not accept what my stepmom, Amatsu Yurina, was doing. I could not see eye to eye with someone who would build an ark to save her own family while abandoning the future of 7 billion people. I just couldn’t. But on the other hand, she was the one who had brought Erika and Ayumi into my family. She had given me a new family, new smiles, and a new daily life. In all seriousness, I might have just curled up in a dark room if not for them. For years and years.

What was truly necessary?

And I’m not talking about justice or humanity. What’s “right” can eat shit. I just wanted to know how to repay this debt.

At the very least, running away from home to preserve my pathetic pride seemed like the wrong answer. Especially when I tried to act independent but found myself reliant on the adults for everything…

“…Today will be over in just a few more hours,” said Himatsuri-san while leaning over the railing and looking down at the peaceful nightscape below the balcony.

In the worst case, we could be sucked into a random puddle the second the date changed. Who would we see there, the giant shark Leviathan or the mysterious Siren?

Just to be safe, I took a bath in advance. Not for any kind of battle preparations; I just wanted to soak in a hot tub while I could. That too would soon be a luxury beyond reach. Safety came with the highest markup. It came at a far greater premium than jewels or artwork.

We had to bring an end to this issue. My mom had given me this life and my stepmom had saved it, so I was sick of gambling it like I was enjoying the thrill.

I couldn’t just search for the “today’s exit” once I got there. That was the same as running away from home: it looked like I was doing it myself, but I was only using what someone else supplied for me.

If I really wanted to change things, I had to step outside that protection. I had to face the true world while exposed to its dangers.

Where would I find the key to ending this?

In the glowing ocean?

Or in reality?

“…How long is this going to continue?” asked Himatsuri-san.

“Until we end it ourselves.”

[Self Record] Legendary Creatures Dictionary: S [Leviathan’s Report]

Siren.

A bird creature from Greek mythology. They look like a beautiful woman or girl, but they are often drawn with a pair of wings and with small birds on them. Also, they are almost never depicted swimming in the ocean.

They are feared for sinking ships when their beautiful song leads sailors astray.

They are not a blatant monster, but there is no mention of an obvious weakness and it is estimated they are the anthropomorphized fear of shipwrecks, just like the Mermaid and Lorelei. In other words, the method of conquering that indefinite fear is not a protective charm to ward off evil. It is definite sailing skills.

The Siren is a symbol of something which takes lives, yet their name was curiously adopted for the sirens of police cars, fire trucks, and ambulances. Their song is now used as a cry of hope informing people in need that their protectors are on the way.

Chapter 4

Part 1

“…”

The ringing of the alarm clock pounded on my head.

Surprisingly, I had made it to the morning. I had not gone to that flooded battlefield. I had taken a bath the day before and not left the bed since, so I simply had not had a chance to touch enough water to take me to that glowing ocean.

Given what had already happened, either the Leviathan or the Siren intended to use their ticket for each day. That suggested they could not store up tickets and then use them all at once. So I could not let my guard down. Somewhere today, they would make an attempt before midnight arrived. Even if that meant using people infected by parasites like the time before last.

“Good morning, Satori-chan.”

“Yeah, good morning.”

My mom apparently didn’t eat breakfast, so there was nothing prepared. I was kind of used to that now, so I opened the kitchen fridge and found a fish sausage to eat. It was a complete mystery what kind of life Himatsuri-san lived, but since I had school, I changed into my uniform and left the high-rise apartment building.

While walking outside, my smartphone vibrated in my pocket.

“Helen> Senpai, I am following the plan.”

After reading the short-message SNS speech bubble, I typed in a quick response and put the phone back in my pocket.

I walked to school like normal.

At the very least, I couldn’t see any suspicious infected people around. But after seeing Tanabe-san at the aquarium, I knew they could blend in so perfectly it was impossible to tell.

…And there was no sign of the supposed Siren.

Once I arrived at school, my smartphone vibrated again.

“Helen> I didn’t see anyone tailing you.”

“…Hm.”

I had asked Itou Helen to walk a bit behind me to see if anyone was following me.

“Maxwell, is there a drone flying above us?”

“No. I cannot detect any control signals. It is possible for them to use an autonomous flight program, but they would still need to send and receive signals for error correction, similar to a radio clock. There was no sign of that.”

“What about a satellite?”

“I cannot account for unregistered guerilla satellites, but I detected nothing of note. 39 weather, military, and civilian topographical survey satellites passed by overhead, but they were all performing a general scan and showed no sign of focusing in on a specific individual.”

…I was doing some pretty impressive things here, but sadly I couldn’t brag about it when I was only asking Maxwell to do it for me.

Regardless, it seemed they were not using a camera instead of appearing in person.

While I changed into my indoor shoes at the shoe lockers, Itou Helen caught up and spoke to me directly.

“What is this about, Senpai?”

“That’s the thing…”

I had explained the details to her when I asked for help, so I didn’t need to hold back with her.

“If the Leviathan is to be believed, the Siren would be targeting me, right?”

“Well, yes…”

“So I was wondering how she would be targeting and attacking me. The Leviathan is inside an aquarium tank here in reality, so I thought the Siren might be in Kukyou City pursuing me like an assassin or sniper.”

“And you didn’t find anything. Then was that shark lying about there being a Siren?”

“That would certainly simplify matters, but I have no guarantee of that…”

Finding something was a simple way of proving something, but not finding something did not prove anything one way or the other. Was there no Siren, or was she simply doing something else at the moment? I had no way of knowing.

And there was one other thing:

“It’s also possible there is a Siren, but she isn’t carefully targeting me like that. Her song might envelop all of Kukyou City. That would be the worst possibility.”

To be blunt, that was my biggest concern. Even that Leviathan had talked about intervening, so (if this Siren really did exist) the Siren’s ability had to be greater than one of the seven deadly sins…

I didn’t know the exact conditions, but in the worst case, she would be able to send hundreds of thousands of people to that glowing ocean on a rainy day. Assuming there was no limit to the number of people she could send at once.

“What I really want to find is that the Siren exists and there are some really intricate conditions that need to be true before she can send someone to that glowing ocean.”

That would mean she had to constantly tail me to track my location in preparation to send me to that ocean. In that case, I could move in and achieve checkmate before her preparations were complete. If I lured her into the shopping district with all its security cameras, I could use Maxwell’s power to its fullest and work out the Siren’s location.

But things changed if she could be anywhere in Kukyou City…or if her contamination could affect such a wide area from outside the city. Then I would be unilaterally tormented to death while trembling in fear of a ghost that may or may not even exist.

Yes, just like before.

It would actually be a relief to learn this was all a lie by the Leviathan, but I didn’t have enough information to say that. The Siren was not here now, but that was no guarantee she would not be a minute from now.

I parted ways with my cute underclassman and entered my classroom.

“Satori-kun.”

There I found my forehead glasses Class Rep standing tall with her hands on her hips and her cheeks puffed out. She was as blatantly upset as Ayumi when Erika stole the popsicle she had been looking forward to after her bath.

“Come here a moment. Sit. On the floor. Now!!”

“In the middle of the classroom!?”

That command came with a high difficulty level, but it was also a wonderfully unparalleled chance to demonstrate my superiority to the class. I would gladly take her up on her offer and enjoy every moment of it. Heh heh heh. Hands off, boys and lesbians. Only I can keep up with this Class Rep!!

“The depressed aura coming from your house is getting intense. There are tons of black cats out front and the roof is covered in crows and bats.”

“…I get the feeling you aren’t joking and my stepmom and Erika really are attracting those things…”

“It’s because you ran away! And running away from home!? You’re just wandering around without the courage to confront them or the resolve to support yourself. Do you seriously think that makes me you look cool!?”

B-bgfhh…!?

I shouldn’t have gotten carried away. That was the Class Rep for you. It had taken me several days of risking my life to reach that answer, but she sent it at me in like half a minute!! Have you ever had your crush stamp your forehead with the words “Hopelessly Smelly Idiot”!? It makes you feel dizzy and nauseous!!

“P-pant, gasp, gasp.”

“No hyperventilating. I’m not done yet. I saw Mrs. Yurina crying. She stepped out the kitchen back door and then broke down where she thought no one could see her, but I could see it from my window. Whatever justice you might think you have, whatever problem you might be dealing with, and however the world might work, I am going to cut you down to size here. Got that, Satori-kun? Here goes.”

Ahhhhh.

It was over. No one could stand up to the Class Rep when she felt a responsibility to do something like this. There was a reason the Class Rep was known as the Class Rep.

“You can fight with your family. You’re human, so of course you’re going to have differences of opinion and issues you can’t back down from. But, Satori-kun, why would you leave instead of speaking with them!? Did you not realize all you’ve done is take any other possibility away from them, given up on them, and sealed the issue away!? I know you did. I know you had to have known what you were doing. You know first-hand how painful it is to be treated like that!!”

The Class Rep had seen it all.

She had seen my family situation from a far calmer perspective than anyone involved. And that was why her words stabbed into me so sharply. Even if the rest of the class did not understand, those words pierced my chest more than any others could.

A family had come to an end when my mom left the home.

There would have been a mixture of feelings behind that decision, but that had been the end regardless. We had fallen apart.

The Class Rep had seen that.

She had seen me lying around like a broken doll after I lost everything.

That was why she was angry.

She was too angry to care who saw this.

Someone who knew that pain was forcing it onto someone else. And onto people he had decided were his family.

I could only listen in silence.

How could I object? What could I do besides remain seated on the floor and hear her out?

“Don’t rely on others and don’t just assume someone else will work this out!! Satori-kun, you should know that what you take for granted and what you believe will continue forever can fall apart and collapse far too easily. So don’t rely on others here!! You have to think about what a single mistake can cause and live a life that works to avoid that mistake. Isn’t that all you can do!?”

I wished she would just hit me.

That would have been far easier to handle.

But the Class Rep seemed to read my mind when she looked me in the eye. She breathed from her nose and responded.

“No. That isn’t my job. So go settle this for yourself, Satori-kun!!”

Part 2

Regardless, it must have been confusing for the rest of our class. But I didn’t really want them all getting into my family life, so that was fine with me.

They made a lot of speculation, but in the end it was summed with the following exchange:

“Well, Amatsu and the Class Rep are always like that.”

“She’s been scolding him since elementary school, hasn’t she?”

I was glad for that.

Afterschool, everything was dyed in an orange light.

“…”

“What? Do I need to follow you?”

The Class Rep was still angry, so I parted ways with her and looked up at a house. It was the one next door to my Class Rep childhood friend.

In other words, my house.

…I couldn’t believe it. It was my house, but I wasn’t ready for this. Besides, if I suddenly disappeared from the high-rise apartment building, I would worry my mom and Himatsuri-san this time.

I looked to the intercom…but it would be weird for me to use that. Given the day of the week, my stepmom would not be standing at a register for her part-time job or at her mom’s club. Amatsu Yurina was there. I didn’t need to call first to check.

The Class Rep really was watching.

At this point, I would have to face my stepmom.

“…I-I’m home.”

I hesitantly opened the front door and called out.

And something seemed intensely off from the moment I did so.

…What was this smell?

Rusty wasn’t quite right. It was like something was rotting…except no, that wasn’t it either. At the very least, it wasn’t something that should be coming from a home.

“Mom…?”

Perhaps I should have turned back.

But without thinking, I slowly stepped inside. Something formless and unknown was encroaching on my territory. That was what it felt like.

It felt more cramped than Amatsu Taori’s luxury apartment, but no part of that house would make you feel lonely.

The entranceway was dyed orange by the setting sun.

There was something on the floor.

“…”

Finally.

Only now did I manage to place the smell. It was an encroaching symbol. An unpleasant stench that should not have been found in a normal home.

It was a salty smell.

The smell of seawater that had gathered in the rocks and rotted.

“Mom!!”

I finally managed to focus properly on the object lying in the middle of the entranceway. It was Amatsu Yurina. The long hair tied back and her tight blouse and jeans were all soaked with sinister seawater. She curled up in something like a crawling position and she trembled while holding her stomach.

But when I started to run over, she unsteadily moved her arm to hold her open palm out toward me.

That hand wet, with a dark red liquid, told me stay back.

“…Satori, have you used up your one-way ticket for the day?”

“?”

“If not, then stay away. Step on the puddle and you’ll be dragged to the other side…”

What did this mean?

That was obvious, you idiot!!

Whether it was the Leviathan or the Siren, they could bring more than one person to that battlefield. That was obvious from the fact that Himatsuri-san and I had been fleeing together.

It wasn’t just us.

While I had been desperately trying to save myself, there had been someone else caught up in it all. While I had run away from home, she had worriedly given me advice over the phone.

It was obvious when I thought about it.

Whoever was behind it, they would be most interested in Archenemy Lilith. So there was always a risk of her being sent directly to that glowing ocean in addition to using me as a hostage!

“But…how? Yes, you’re Lilith, a major demon lord, so you should be able to easily defeat a normal Archenemy like a vampire or zombie…”

“Ha…ha ha. You overestimate me. Maybe I scared you too much at that abandoned hospital. Things can change based on compatibility and the specific conditions.”

Still curled up on the floor, my stepmom forced a smile. So I wouldn’t panic, run over, and step in the puddle.

“But…if you haven’t used your one-way ticket yet, then we simply missed each other. I should have returned immediately instead of sticking around. What a basic strategic error. Ta ha ha.”

“…”

What was this?

Did that mean she could have easily escaped on her own, but she stayed in that dangerous flooded battlefield to search for me in case I was there? While isolated and surrounded by a giant shark, a Siren, parasites, and infected people, she had ignored the dangers to herself and gone around calling my name? And that’s why this happened to her…!?

How…

How could I be so stupid!?

Why had I run away from home and felt I couldn’t look her in the eye? If I had at least agreed to call home at a set time or otherwise set up a way to let her know if anything had happened to me, she wouldn’t have had to search for me in vain!!

The Class Rep’s words pierced my heart anew.

Family was not an absolute for us. I had seen it shatter before my eyes once before. So I had to live my life while thinking about what a single mistake could cause. We had to respect each other. That was all so true.

What parent could sit idly by knowing their child was occasionally setting foot in a deadly world? Of course she was going to find a way to go there too. And would a parent in the same situation tell their child about it? When doing so would only invite their child to follow them? Of course they would keep it a secret!

I had built a simulator like Maxwell and I couldn’t even predict something as simple as this!?

“No, Satori…”

Still curled up and giving off the stench of rotten sweater and blood, my stepmom desperately got the words out.

I could not run over to her or hold my hand to the wound in her stomach.

It was the water.

The great maw of the giant shark or Siren was in the way…!!

“Don’t give into emotion. You decided to bring humans and Archenemies together in a different way than the Bright Cross, remember?”

“Kh.”

“So you can’t. You can’t give into the feeling roiling in your chest. That only leads to the same bloody path of retribution as the Bright Cross…”

“But…”

Was she telling me to overlook this?

Was I supposed to use my stepmom’s blood to get past this? Was she saying that was the right thing to do?

But I had never been trying to do the “right” thing! I just couldn’t stand to leaving someone alone when they were crying and I couldn’t bear to see blood!! I had wanted to protect Erika and Ayumi and I had wanted to side with Itou Helen the Witch, Muramatsu Yukie the Dark Elf, and the others to stop the Bright Cross’s oppression. That was all. That was all it was supposed to be, so how had it ended up like this!? Why was I kept from acting here and forced to overlook the person who had done this to my stepmom!?

“…It’s the same…”

My stepmom, Amatsu Yurina, spoke in a trembling voice. I doubted it was just the pain. She was trembling because her injury was threatening to take away her son’s dream.

“That same feeling is what created the madness behind the Bright Cross.”

…What was I supposed to do?

I doubted the Leviathan or Siren would stop with this. Who would be next? Erika, Ayumi, the Class Rep? Did I have any reason to think Itou Helen or Kuroyama Hinoki would be safe? We were up against an Archenemy that only needed to point at someone and register them to drag them into that glowing ocean. Then they would be in that sunken battlefield containing a giant shark, a Siren, parasites, and infected people.

Would I try to talk?

Or would I try to fight?

Either way…

“…Mom. Even as a great demon lord, I can just send you to the hospital like normal, right? You use normal medicine when you get a cold.”

“Satori…?”

“Maxwell, call an ambulance. They can only drag down someone who was chosen, so the EMTs should be fine.”

My stepmom had to have just returned from that deadly world. She was soaking wet and curled up in the entranceway with a puddle of sweater and blood surrounding her.

There was an “entrance” there.

I still had my one-way ticket. I would find the culprit if I passed through there. Whoever it was, that piece of shit had done this to my parent!!

“No, Satori!!”

I did not bother listening to her.

I took a large step.

And for the first time in my life, I chose for myself to step onto that hellish battlefield.

Part 3

Based on the ground level, the glowing ocean’s water was 15m deep on average. The residential district full of short houses was entirely flooded. And when starting indoors, it was a lot like a maze.

“…”

But there was a difference between being dragged down when you least expected it and diving in yourself. There was no lost time. I swam across the entranceway, through the living room, and out the glass door that had already broken from the water pressure. From there, I just had to swim straight up in search of oxygen.

Would I make it in time?

I would make sure I did.

More than the oxygen, I was afraid of getting decompression sickness from rapidly swimming up more than 10 meters without diving equipment.

“Bwah!!”

My face broke the choppy surface. The rain was blowing in the wind as usual. The water would be giving off a damp blue glow, but even with thick clouds covering the sky, it was before sunset. Like a lit movie screen, the glow-in-the-dark paint glow was drowned out.

There was no point in fighting the current. I focused only on staying afloat and let the current carry me while pulling out my waterproof smartphone.

“Maxwell, check the situation.”

“Sure. The location of the ‘today’s exit’ door is unknown. Nor do I have any information that could act as a hint.”

With the blackout caused by the flooding, we could not use the security cameras. Maxwell’s vision was almost entirely limited to my smartphone’s camera.

So if I couldn’t see something, neither could Maxwell. Along the route to the garden, the glass had been shattered by the water pressure and I hadn’t seen any other windows or mirrors.

“But since injured Mrs. Amatsu Yurina had arrived inside the house and the puddle did not stretch outside as if she had crawled inside, it may be quite close by. Yes, for example, one of the doors within the Amatsu house.”

If so, swimming out into the current had only distanced me from the exit. But I wasn’t afraid. I had to appear on the battlefield if I was to do what I came here to do.

It all came down to whether I could find a starting point in the residential district that was like a giant lake with no land. Whether it was the Leviathan or a Siren, someone here was violent enough to injure Archenemy Lilith too badly to move. I couldn’t just float around like this.

Just then…

“…?”

I saw a massive silhouette directly below me. Yes, it was the size of a submarine.

It parted the surface of the water such that I ended up on its back.

The Leviathan!?

“You do not mind if I speak, do you?”

Once that voice sounded directly in my brain, I found myself as motionless as I had been in the aquarium.

“I avoided this before as you would have stopped moving and drowned, but I cannot just watch. And the risk should be reduced like this.”

Damn, I can’t move a finger… Even if it isn’t trying to attack, this is not fun!

It was incredibly sturdy despite the powerful wind and surging water. I felt more stable than on a building rooftop.

“I cannot recommend performing a search for the Siren. I have searched all around myself, but I have not found any sign of her.”

So that was why.

But there was something else I wanted to know right now.

“You may speak.”

“…Did you know?”

“Know what?”

“That my stepmom, Amatsu Yurina, had been setting foot in this shitty ocean to search for me!? Did you know and then hid it from me while I was at the aquarium!?”

“Of course. Who do you think asked me to drive you toward the exit? Of course, I would have done it whether Lilith had asked or not.”

Again.

It came down to my stepmom again. I was the only one who didn’t know while she was risking her life to protect her stupid son who kept charging headlong into danger!!

“Do not feel bad, boy. No child is aware what their parents do for them. In fact, a parent that did tell their child every little thing they did for them would come off as patronizing.”

“This doesn’t mean I trust you.”

“Nor should you. I have no intention of butting into your familial bonds. I merely wish to keep a promise I made with my old friend Lilith.”

…I had discussed this on the phone with my stepmom.

At the time, she had suggested this was a conflict between those standing at the peaks of different deadly sins, but how much of that had been the truth?

If what I had just heard was true, the Leviathan had already been working to drive me toward the exit by the time I first entered this world through the apartment bathtub. Which meant my stepmom, Amatsu Yurina, had already made her request.

The more I saw, the more I realized how small and ugly I was. Both Lilith and the Leviathan operated at another scale altogether.

“So what will you do?”

The Leviathan apparently did not intend to keep me paralyzed while carrying me to the door and forcing me through. The giant shark understood what my stepmom had been feeling, but had no intention of restricting her son’s freedom. This demon lord was quite the educator.

“Let me off at a group of buildings. I can’t rely on you forever.”

“I like the look on your face now, but as I said, the Siren will not be easily found.”

“True enough.”

There was no way to search everywhere. For one thing, we had no idea how far this field went. Did it only cover Kukyou City? Did it cover the entire world? Or did it extend to the entire universe? The difficulty of a thorough search would change accordingly.

At the same time, I thought the Siren had to be nearby if she did indeed exist. She had to be somewhere in this city. If she was directly attacking me from the other side of the planet, there was nothing at all I could do.

With that in mind…

“There is one place you haven’t checked.”

“Where exactly is that?”

“Hey. A Siren is an Archenemy like a Mermaid or Lorelei that uses her beauty and singing to lead sailors astray and sink their ships, right? But instead of having a fish tail for legs, she has large wings. Probably due to a connection with sea birds. In that case, I can see how a lord of the ocean wouldn’t find anything.”

I wanted to point toward the heavens as I spoke, but unfortunately, I could not move a finger.

So I used my words instead.

“The sky. If she flies up above those thick rainclouds, no one on the surface would ever be able to find her.”

Part 4

Here, things worked differently than in reality.

Normally, if the Siren was flying above the clouds, she would be seen by radar and satellites. There were apparently even precipitation radars that used terrestrial digital broadcast signals. But the flooding and blackout had destroyed all of that communications infrastructure in this blue battlefield, so all that equipment meant nothing.

If you could hide it from the surface, you could distort reality.

The altitude of the clouds depended on the type, but I could assume it was between 2000 and 3000 meters. Clouds had weight, so the thick rainclouds full of moisture tended to be lower. Going there myself would require a helicopter or airplane, but the flat airport would be underwater and the equipment was all too specialized for me to use anyway. Kukyou City had the ocean and some mountains, but none of the mountains towered high enough to break through the clouds.

But those were not my only options.

This was the glowing ocean.

It was not the same as reality. If that was how they were doing things, then I would play along. It was time I found a clear answer. If the Siren existed, I would pull her down from the sky. And if I proved she didn’t, then the Leviathan was my enemy.

“This is good enough. Let me off here.”

“But…”

“Let me move again.”

The Leviathan’s voice stopped. At the same time, I could move my arms and legs like I wanted. Its giant body was stable despite the wind and waves, so I did not have much difficulty.

I moved from the giant shark’s back to a point partway up a half-flooded building under construction.

I said one last thing.

“I’m hoping you aren’t my enemy.”

The connection had already been broken, so there was no response. I moved from building to building and the Leviathan dived down into the water.

A social media speech bubble spoke to me on my waterproof smartphone.

“What will you do?”

“I’m about to give you the specific instructions. We’re going to smoke out the Siren behind the clouds and bring her down to the earth.”

“No. That is not what I was asking about.”

“…”

I didn’t know what it was I wanted to do.

If I was willing to enact vigilante justice on an Archenemy as long as I could justify it with a personal motive, then my stepmom was right: I was no different from the Bright Cross that had been hidden below the city.

At the same time, I did not want to unconditionally submit to anything an Archenemy might try to do to me.

I wanted use to be on equal footing.

I wanted us to all smile together.

That was all I wanted, so why?

“Anyway, if this Siren really does exist, I want to meet her in person. Even if we just need to talk, we can’t solve anything if she’s looking down on us from the heights.”

“Sure.”

Now it was time to discuss the actual method.

How was I supposed to bring down the Siren when that Archenemy was flying around at an altitude of at least 2000 or 3000 meters?

I had no way of flying up above the clouds and I couldn’t fire tens of thousands of antiaircraft bullets or surface-to-air missiles to establish a barrage.

But how could I just give up here?

The answer was all around me.

“Maxwell, check the disaster environment simulation map of Kukyou City for the distribution of flammable gases. And I don’t mean the city gas inside a maintained underground pipe network. I’m mostly interested in homes and restaurants that use propane tanks. If that isn’t enough, check the discount stores and hardware stores. While they won’t be as powerful, the small compressed gas cylinders for portable stoves can function as a weapon if you gather enough of them.”

“Are you planning to create brutal rockets using thick metal tubes?”

It would certainly be neat if I could do that, but there was no way to ensure their accuracy. In aerial battles, targeting was far more important than power or firing distance. I only had one option since I could not prepare a weapon that linked its radar or IR sensors with the minute movements of its guidance fins.

Instead of targeting a point, I had to cover the entire area.

Assuming she was up in the sky, I had to fill every single gap, so she would be hit no matter where in the city she was flying. I could not overlook a single pinpoint.

“I’m going to detonate them across the entire city,” I said.

This felt a lot like being in a simulation because nothing I did to this glowing ocean would happen in the real world. I didn’t have to worry about destroying it. And thanks to the memories of my fight with Erika, I was getting more and more accustomed to the fear of the surging water.

“Then we ensure an incomplete combustion to send dark smoke all across the sky. With all this water, there should be tons of wet flammable objects…like paper or trees.”

“Sure. In other words, you are using chemical warfare.”

This was the glowing ocean they had created. They were the ones who had ignored the rules of reality. So it was time I used that supposed advantage against them.

“Now, then. How long can she continue struggling once updrafts created by the heat of the flames fill the dark sky with carbon monoxide?”

Part 5

I didn’t need to be very careful at all.

Whenever I found a gray propane tank, I messed with the hose a bit and set it to explode a few dozen seconds later. There were no firefighters here, so once the fire got started, no one would prevent the entire building from burning. Even the blowing rain and rushing floodwaters were not enough to put out the fire in the structures rising from the water’s surface.

And those giant buildings were made from a great variety of materials, so once the fire spread, it belched black smoke into the sky. The blowing wind was not enough to erase it and it simply spread thinly across everything.

I kept moving on to the next building before the flames and smoke could reach me.

“Maxwell, let’s do this building too. Let’s check to make sure there isn’t anyone inside.”

“Sure. Calculating meteorological conditions based on data from the camera and microphone. Updating predicted distribution of carbon monoxide.”

When a building didn’t already have a propane tank inside, I would throw a small gas cylinder inside like a Molotov cocktail. As long as there was no one inside, I didn’t need to hold back. I would burn it all, whether it was a broadcast tower or the city hall.

“Next, Building 6.”

“Once we’re done with that, let’s take the rubber boat to another block. We’ll cover the entire city with smoke.”

When the giant shark was not attacking, I only had to fear the leech-like Remora parasites and the infected people. If the Leviathan was telling the truth, then they would have been the ones who hurt my stepmom. Had an infected person’s teeth or nails gotten her, or had a Remora parasite gotten inside her body and she had to forcibly extract it?

But while they had the violence of numbers, they lacked the giant shark’s speed. I could lose them if I used a rubber motor boat to travel across the water at nearly 100kph.

“If we’re gonna do this, we might as well go all the way.”

“Sure. The central financial district’s business region is up next, so we will have plenty to choose from.”

“Oh, yeah! I always hated those fancy restaurants that always say they’re full up from reservations but never actually intended to let you in in the first place!”

We went around a few more blocks, setting more fires.

Thinking back, whoever was behind this had stepped up the attack during the third and fourth days which we fought back-to-back. So what had happened on the second day before that? I didn’t even need to check with Maxwell: the Leviathan had gone on a rampage and started a major fire at the industrial complex.

If that had motivated the intensified attacks, then this would work. They didn’t want any kind of major fire in the city.

But to settle this, I would need an even large conflagration than that. We had already proven that a fire in a single industrial complex was not enough to bring them down from the heavens.

So it came down to numbers.

If one was not enough, we just had to make even more.

“The density of carbon monoxide in the air is rising. Be mindful of the wind direction.”

The black smoke rose into the sky. So would the carbon monoxide riding the updrafts created by the fires. The blowing wind would spread it out, so there would be no gaps once it arrived high in the sky. The black smoke rising from multiple fires grew as thick as a coat of paint and finally transformed the entire sky into a field of death which could not be inhaled.

Things were pretty bad down on the surface, but it had to be even more hellish up there.

“If my calculations are correct, the sky is now a danger zone.”

“…So it’s about time.”

The Siren was an Archenemy – an immortal. Since the extreme low temperature and limited oxygen of the sky was her home, she had to be far tougher than humans like us.

But you aren’t invincible.

The Leviathan said you Sirens belong to the ocean but live in the sky. That means you can’t live a purely aquatic lifestyle. I don’t know if a silver bullet or consecrated knight’s sword would work on you. But while it might be on a different level, you’ll still “suffocate” without air to breathe, just like a human.

So come on down.

Come down from those black-stained heavens and prove it.

Prove you’ve been sneaking around behind the Leviathan as the true culprit! Prove you’re the piece of shit that dragged the entire city into this and harmed my stepmom…my family!!

“Warning.”

“Kh.”

When Maxwell warned me, my head jerked up to look at the sky instead of my smartphone.

Some kind of golden light broke through the thick black clouds.

No, wait.

It wasn’t just falling. It was headed this way!?

“Brace for impact!!” warned Maxwell.

“That won’t be enough!!”

I didn’t have time to hesitate.

As soon as I jumped out of the rubber boat, the falling golden Archenemy tore through the rubber boat and smashed it to smithereens.

Part 6

I had fallen into the rapid current.

Without the boat supporting me, I was swept away. That filthy water was full of dangers, like those strange parasites wriggling through it

“Ha ha.”

But I still laughed.

I reached for the wall of a building rising from the water and I clung to it.

“I found you, Siren! I’ve revealed the true villain!! Ha ha ha ha!!”

The Leviathan hadn’t been lying. It hadn’t been tricking us and hurt my stepmom. That was enough to make me laugh uncontrollably.

And I had brought the real villain down from the heavens.

I had successfully shoved their face into the same waters that had swallowed up everyone else.

Why was it?

I couldn’t stop the dark laughter rising from the depths of my gut. I felt so much accomplishment from the filthy action of hurting someone. It felt just like clearing the brutal dungeon in an RPG that appears only after defeating the final boss.

“Warning,” said Maxwell. “User, this is no time to be crying. Please stay focused.”

“…”

Crying? Me???

Wasn’t that just the rain? I didn’t know what that was about, but I didn’t have time to find a mirror and check my face.

She was here.

Archenemy Siren.

The villain behind it all.

She had torn through the rubber boat and plunged into the water, but she had floated back up to the surface. She indeed seemed to have trouble moving in the water. But the sky was filled with the black smoke and carbon monoxide carried there by the updrafts created by the heat of the fires. As a result, she could not go up or down and could only float at the middle area where I could reach her.

This was a rare opportunity.

She was finally in reach. If I did not settle this here, it would be difficult to turn things around again.

And yet…

“Wha-…?”

My eyes widened when I saw the person frozen place as if ignoring gravity and standing on the water’s surface.

They had a partially-matured body that seemed on the borderline between girlhood and adulthood. She had some loose white cloth wrapped around her, but there did not seem to be any clear sleeves or hems. She may have been more half-naked than anything.

Her wings were combined with her arms. It would be more accurate to say the long, long blonde hair growing from her head was wrapped around her arms to create a silhouette that resembled golden wings. A Siren was apparently a lot like a Mermaid or Lorelei. This may have been similar to how Kuroyama Hinoki the Mermaid created the shape of a tail fin from her long black hair.

But that was not the issue.

I recognized her.

I also knew that long, long blonde hair from somewhere. It was usually worn up in some kind of cabaret girl style I didn’t know the name for, but when let down, it would probably reach past her waist and to her ankles.

I spoke the name of recognition that would not vanish from my mind.

“…Himatsuri…-san…?”

[Self Record] Special Booklet: Legends About Hair [Leviathan’s Report]

Demons reside in women’s hair.

Surprisingly, that legend can be found all around the world. As an example, there is a widely followed ritual of cutting one’s hair after heartbreak to purify the hart and bring an end to a bad influence.

On the other hand, it is said evil power resides on a woman’s hair after it takes in a demon. As an example of that, there is the Greek legend of Medusa whose long hair became venomous snakes and who became a symbol of something impregnable that cannot be approached from any direction. She is most famous for being a monster with petrifying eyes, but while her eyes could only face forward, the snake hair left her with no blind spots in any direction.

While it is not as extreme, the later legends of Western Witches and Succubi said they seduced men with the power residing in their hair.

…Now, the editorial department of Monthly Chu Chu can’t just overlook this! It might seem a little soon, but now’s the time to get started! For Halloween this year, I’m definitely using my long hair for a great transformation!! I’ll turn myself into a cute witch that would even shock those French noble ladies who used to place models on their head to turn their hair into something like a diorama. Have faith in Lady Gonzou’s feminine power after 30 years of Onee life!!”

Chapter 5

Part 1

When I thought about it, I realized I knew next to nothing about Himatsuri Asami. She had no trouble speaking with my mysterious mother and she had run away from her own home. But that was all I knew. I had no idea what she was doing there or where she had come from.

No.

More than that, I didn’t even know if she was the real Himatsuri Asami.

That was a shocking truth, but I couldn’t stop thinking.

After stopping near the water’s surface, the Siren took in a dep breath and opened her lips just a crack.

A high-pitched whistle exploded out and my entire body, down to the fingertips, stopped moving.

Was this the Siren’s song!?

I couldn’t support my body, so I slipped from the building wall and was once more swallowed up by the current. The only upside was that my fingers froze in place with the smartphone in their grasp. If I had let it go in the surging water, I never would have seen it again.

But what was I supposed to do?

I couldn’t swim like this. Nor could I breathe properly. On top of that, I felt something like a solid gummy hitting my arms and legs in the muddy water.

Were those the parasites? The Remoras!?

They had not managed to actually attach themselves yet, but it was only a matter of time!!

“…Gh, bh…”

I could not even scream with control of my throat taken. Was it all over? Would I suffocate in the water and have my body infested with strange leeches?

But just then, something as large as a small island rose up below me.

It skillfully supported me so I did not roll off in the wind and current.

“What did I tell you? I will give you permission to speak.”

“Bwah!? Leviathan!!”

“That Siren has the twisted power to submerge an entire city in this lost sea. You should have known what would happen to your mind if you challenged her without my support.”

Dammit…

Even after all this, I had to rely on someone else’s power, just like I was running away from home again!

“On the other hand, dragging the Siren herself down here is deserving of praise. Leave the rest to me.”

“…What are…you going to do?”

“She originally belonged to my organization. It was my failure that led to this chaos, so I will punish her myself. I will end this by crushing her with my teeth. That is my duty.”

“…”

“Do not feel bad. This is a matter of my organization. No matter how much blood might be shed, you need not dirty your hands. You continue working toward your ideal.”

Was that how it worked?

Was that acceptable?

Was I…afraid of dirtying my hands? Was that why I claimed to be a pacifist? No. Who did the dirty work wasn’t the issue. I had wanted to see humans and Archenemies getting along. It would all fall apart if I rushed to a conclusion and doomed an Archenemy to a sea of blood! Isn’t that how it’s supposed to work!?

I realized the truth at the last second.

And I worked to stop it.

Simple and heroic anger was toxic. The more you wielded violence, the more pleasure you would feel. The crushing weight of the guilt would come later, so you would search out a new target to distract yourself from it. Once that began, you could never stop.

“You can’t…do that.”

“Why not?”

“Leaving this to you would be the same as turning a blind eye to the Bright Cross so they could handle all the dirty work.”

The Leviathan fell silent for a moment. And then it spoke.

“If you reject every course of action, you will quickly find no path forward in your life.”

“…I know that.”

“But I will respect your decision. You have one chance. If you fail, then I will end it. So do not worry about what happens afterwards. Give it your all.”

I couldn’t quite tell if it was trying to encourage me or threaten me.

I did not know what Himatsuri-san’s goal was here. Or even if that really was Himatsuri-san. Was she taking on someone else’s identity, or was someone else taking on her identity? I knew nothing here.

And what was it I simply could not back down on here? It was not some stupid macho desire that confused punishment with justice. What did I really need here?

To return the Remora-infected people to normal.

To ensure no one would be taken here again.

To end this conflict and confrontation with my stepmom.

…I would not take no for an answer. No matter what, I would make sure those three things happened. Anything else would count as a loss for me.

“I will support you,” said the Leviathan. “We will be unable to speak, but the link will remain. I will do the best I can to fight the Siren’s interference, but I do not know how successful I will be. So be careful.”

Strength returned to my numb and unmoving fingertips.

“…”

I grabbed the nail file I had used as a flathead screwdriver.

I wasn’t afraid of the floodwaters. I could reproduce this in the simulator.

“I assume you can hear me, Leviathan. Take me to the Siren.”

Even without a response, I could tell it could hear me.

“Her brutality is concentrated in that song. That’s how she sends people to this glowing ocean and messes with people’s heads.”

It was unclear how she worked with the Remoras, but I doubted the leeches were carrying around headsets. I guessed the airborne Siren located a target and used her song to instruct the Remoras to attack it.

Or maybe she could directly control them with her song.

“…So I’ll settle this by taking out the Siren’s throat. I don’t have to prevent her from speaking altogether. Just like treating a cavity or swollen tonsils can change your voice, a small wound should take away her optimal voice quality.”

I knew this was a cruel thing to say.

It was like attacking the Achilles’ tendon of a man whose life centered on playing soccer, but claiming it was okay because he would still be able to walk once he healed. Being taken from the forefront was the same as taking his entire life from him.

But that was a compromise I was just barely willing to make.

As long as I could end this without taking anyone’s life.

I of course knew she was not going to like it.

The Leviathan’s giant body parted the floodwaters, shot straight toward our target with enough force to split the sea, and approached the Siren floating just off the water’s surface. Her eyes wavered up and down for just a moment. She was not sure who to attack: me or the Leviathan.

Normally, she would be more concerned about the 30m shark than a puny human.

Just before collision, the Siren’s eyes dropped down.

…Now!!

“Ooooahh!!”

With a yell, I ran across the Leviathan’s back and leaped forward. And I held the nail file I used as a flathead screwdriver so I could stab the center of the grip into her slender throat.

Just then, the color gold fluttered around.

I had no idea what happened.

I simply felt a heavy impact pass through my entire body. It came from my jaw. Something had hit me there. My vision blurred, I lost balance in midair, and I fell into the water.

…Damn.

I had come so far yet I was dealt with like an afterthought…

Part 2

My head was shaking.

I fought with my unfocused eyes to pull together an image.

I saw a ceiling.

As soon as I realized I was in the guest room of my mother’s apartment, someone peered down at me.

“Oh, did you finally wake up?”

“…Himatsuri…-san…!?”

I wanted to jump to my feet, but my body refused to move.

What had happened back there? Was Himatsuri-san really the Siren behind all this? Or was someone else pretending to be her? If so, what was the connection between her and the Siren!? They wouldn’t do that without good reason!!

“What’s the matter? I wasn’t there this time, but were things especially bad? Not that risking your life in that shark’s place is ever going to be pleasant.”

…What did this mean?

Was she playing dumb? Even though we were the only two ones in the room? If not, did she really not know what had happened? But how could she not? Did she lose her memories of what she did as the Siren?

As far as I could tell, Himatsuri-san was the same as always. I guess I would say it seemed unnatural that she did not respond at all to what had happened.

“There is…something I want to ask you.”

“What is it?”

Puzzled, the beautiful girl, who had cabaret girl blonde hair and a champagne-colored dress, tilted her head.

“…How did I get to the apartment? I entered the glowing ocean from my actual home.”

She must have sensed an odd nuance in that because Himatsuri-san narrowed her eyes somewhat. And since she stood on the side of my mom, Magatsu Taori, it was not necessarily a welcoming light in her eyes.

“I don’t know. Taori-san carried you back, but didn’t say anything about it. So where was the exit this time?”

“…”

Since my stepmom, Amatsu Yurina, had been curled up at home, it should have been somewhere in that house.

I found it hard to believe my mom would approach that house now. Not to mention setting foot inside. So had the Leviathan set up multiple exits around the city?

…That was probably the case.

I didn’t know how many people were being dragged there by the Siren’s song, but if there was only one exit, they would all have to rush there. So what about when it was that industrial complex’s blast furnace or that inn’s detached room? Those places were off limits and Himatsuri-san and I had only managed to sneak out with Maxwell’s assistance. Looking at the reality side of things, it would have made the news if 100 or 1000 outsiders appeared there. Besides, where were the Siren and Leviathan getting in and out? It seemed like multiple exits was the best way to think about this.

But I doubted I had left the exit on my own after passing out.

So…had the Leviathan saved me?

“Oh, right. What happened to the Leviathan!?”

“Eh? That giant shark?”

Himatsuri-san sounded somewhat creeped out. That reminded me that she had not been with me at the aquarium, so she still saw it as a man-eating shark. She wouldn’t know that it could speak human language.

But what had it done after pushing me out of the “today’s exit” door? Had it returned to reality through a large aquatic gate near the aquarium? I doubted it. If it was to be believed, then its greatest enemy had finally been brought within reach, so would it really turn tail and run?

Something had to have happened.

Himatsuri-san was here and with no memory of being the Siren. That was a mystery in and of itself, but something must have happened. They would not just have parted ways peacefully.

“…Himatsuri-san.”

“You look pretty grim. Did something really happen?”

I breathed in and out.

If she was simply playing dumb about being the Siren, then I might die here. Being nearby was enough for her song to scramble my brain and her straight claws had shredded the thick rubber rescue boat. That was superhuman ability, so my windpipe would be a simple task.

“What does the word ‘Siren’ bring to mind?”

But I still said it.

I couldn’t put it off any longer. The Siren had attacked my stepmom and she could attack anyone next time. I couldn’t let that kind of tragedy happen again. I wasn’t just an observer. More than half of the fault for what happened to my stepmom lay with me.

So it was my turn to protect.

I would protect my parents, my family, my neighbor, and everyone else I could think of.

When she saw the look in my eyes, Himatsuri-san fell silent and sighed. Perhaps due to her manicure, her beautiful nails shined like a blade as she moved her fingers.

I felt my heart pound extra hard in my chest.

But I did not take my eyes off of her.

Then she pulled something from her cleavage and tossed it to me.

It was a smartphone.

I thought I had destroyed hers and thrown it into the floodwaters to escape the Leviathan, so had she gotten a new one?

“?”

“Check the screen.”

I did as she said and saw a photo album management app was open. She had apparently restored the data from a backup. A single photo filled the screen.

It was from a bit too close up, suggesting it was a selfie.

The limited space was filled by two girls.

…Two?

Yes, that was right. It must have been an older photo because the two blonde girls looked my age or a little younger and they fit themselves in the same photo by pressing their cheeks together.

“This is why I’ve run away from home. It’s all very silly, though,” said Himatsuri-san. “Her name is Minaki, written with the characters meaning beautiful, cry, and happy. I was told she was a relative and I had always believed it. We only met once or twice a year, but I always looked forward to the Bon Festival and New Year’s because of it.”

Nothing about it seemed odd, but one phrase threatened to tear it all down.

She had said, “And I had always believed it.”

“Minaki was apparently an illegitimate child. She was my younger sister.”

All sound vanished.

Every last decibel in the room faded away.

“Once I knew the truth, I could find all sorts of clues from the past. There was a cousin and an aunt, but I had never seen the uncle. These were supposed to be family reunions, but Minaki and her mother always showed up late so they missed the main gathering. …And I had never once seen Minaki speaking with my mother.”

…This was a family twisted in a different way from mine.

There was no point in comparing the two…

“You can say adults don’t play fair as much as you want, but actually seeing that reality before your eyes is so much harder.” Himatsuri-san placed a hand on her forehead. “…My father was a workaholic. He increased his social status to fight back against society and earned lots of money to fight back against his family. He put himself first and there was no benefit for us. So it was a shock to learn he had given his love to someone else, but that was honestly a trivial matter. I mean, without that mistake, Minaki never would have been born. It was a complicated feeling, but I could have put up with that.”

“…”

“What I truly couldn’t forgive was that he was giving money to Minaki and her mother. Those visits I so looked forward to were really so he could hand over a bunch of cash. …That solved it. If she had wanted to, she could have brought it to court and torn my family apart, but my father solved it by tossing some cash onto the table looking as irritated as can be. That wasn’t love. I couldn’t understand it. To him, humans were no more than status symbols, like a foreign car or a brand-name bag! It was only because Minaki and I had grown too much that our mothers were considered a mistress and a wife. He had plenty of other people, but they were just like brand-name bags he bought just to buy and threw into the closet without even opening the box!”

No one would talk about that. Not Himatsuri-san’s family and not Minaki-san’s.

So how had Himatsuri-san learned about it?

…That was obvious: she had seen it for herself.

This girl had been more important than a friend and she only saw her twice a year: during the summer and during the winter. While excited about finally getting to play with her again, she had seen it.

Perhaps through a cracked door.

She had seen familiar people holding the worst possible conversation, she had seen people she cared about only able to bite their lips and accept it, and she had seen the trembling fingers reaching out toward the cash slammed violently onto the table.

And that could have been her.

Those people were like abandoned bags or shoes, some arbitrary order had decided who was the proper family and who was the mistress’s family, and the two sisters were forced to keep their heads down by their mothers.

“Um.”

I had no idea what to say. I could only pray that Himatsuri-san met someone like the Class Rep was for me. Maybe that was who my mom was.

All I could say was…

“…So are you not an Archenemy yourself?”

“Isn’t that obvious? I’m just a human. If I had that kind of power, I would have killed that man already. To free us all.”

When speaking in terms of her mother, she had called him her father, but now she just said “that man”.

“…It must be Minaki’s mother. That has to be why Minaki has that power. And if they do have that kind of power, I’m impressed they haven’t used their claws or fangs on him.”

…Ah.

I finally, finally felt like I had reached the heart of the issue.

The situation was not actually what Himatsuri-san thought it was. Minaki-san had thrown the city’s people into the glowing ocean and had gotten Himatsuri-san herself involved.

But what was it the Leviathan had said?

Sirens belong to the sea, but they fly through the sky. So they might have a connection to beings on the land. The Leviathan’s group had not cared what the Calamity did to the surface. But the Siren could not just ignore it. So she had challenged my stepmom who had put together Absolute Noah and she might be trying to find another way of overcoming the Calamity.

How could this be?

In that case, what was it the Siren – Minaki-san – had wanted to protect them by betraying her old sea organization, challenging Absolute Noah, and making an enemy of actual demon lords like Lilith and the Leviathan?

No matter how much she flapped her wings, her freedom had been taken from her and her head held down.

She was a bird trapped in a cage.

But had she still been trying to protect Himatsuri-san’s family!?

…How?

How much would you have to care for someone to make that kind of decision? The slightest dark emotion or desire for revenge would have led her to abandon them. She would not be destroying them herself. It would be the Calamity destroying the Himatsuri family. If she used that excuse, it would have ended at the very first step and nothing would have happened.

But the Siren refused to accept it.

She would not allow the Himatsuri family or the people who lived there to drown in a sea of blood and suffering, no matter who caused it to happen. And to prevent it from happening, she had directly challenged a giant organization controlling the world from the shadows.

“…She looked forward to it.”

“?”

“No matter what the real reason was, Minaki-san still looked forward to seeing you, Himatsuri-san. She still looked forward to laughing and playing with you. That’s the only explanation!!”

“Wait, what are you talking about!?”

…After all, there was no darkness at all in Minaki-san’s photographed face. If she was putting on an unwilling act, there would have been something there, but I couldn’t see any hint of it on her face on that cheek-to-cheek photo.

Who was right?

Who was wrong?

Himatsuri-san was not the Siren. So was Minaki-san still in that blue battlefield? The Leviathan had to have gone right back into those floodwaters after pushing me back to reality.

How much time had passed since then?

The Siren could not breathe underwater and the black smoke from the fires had filled the sky with carbon monoxide. Minaki-san could only remain just above the water’s surface, making her the perfect target for the Leviathan. And the Leviathan would not overlook that opportunity. It would finish her off.

“Maxwell, Minaki-san is in danger. Is there any way to go save her!?”

“No. You can only access those uncertain coordinates once a day. You lack the rights.”

Dammit!!

But Minaki-san had to know she was at a disadvantage. That was why she had remained above the clouds to hide in that safe zone out of the Leviathan’s reach.

In that case…

“Minaki-san must have returned to reality. That’s the only way for her to escape the Leviathan’s jaws.”

She had to have returned.

The Leviathan was unstoppable there but restricted to an aquarium tank back in reality. You might be at risk in the ocean, but it could not reach you on land. Reality gave you better odds of protecting yourself and healing any wounds.

“Where is Minaki-san in reality? If she can move back and forth between the two areas, she must have some kind of hideout. And inside Kukyou City. She has to be there.”

Of course, I had to think of Minaki-san as a threat. Whatever her goal may have been, she had used her song to send quite a few people to that glowing ocean and she had infected them with the Remora parasites. She had also injured my stepmom.

I had to keep Minaki-san from acting before the Leviathan got to her and I had to prove something.

Prove that she had to pay for her crimes, but there were ways of doing that without killing her!!

“Wh-what are you talking about? Minaki is in danger? Was that girl dragged into the water too!? Hey, what do you mean!?”

Himatsuri-san grew pale and grabbed at me.

She was looking at this the wrong way around, but I felt like I understood why Minaki-san would risk her life to protect Himatsuri-san. This was the kind of person Himatsuri-san was, so Minaki-san had wanted to return the favor. Even if they had different mothers, they were still connected by blood.

Telling her the truth would be hard.

Minaki-san was behind this and she was doing this awful thing for Himatsuri-san. And since she had put Himatsuri-san in danger, Minaki-san may have lost control.

However…

“Warning.”

Maxwell sent a silent message.

“If Miss Asami has not used up what Mrs. Yurina called the ‘one-way ticket’, she might access those uncertain coordinates to search for Minaki. She will meet the same fate as Mrs. Yurina when she stayed longer than necessary to search for you.”

“Kh.”

Even Archenemy Lilith had barely survived. And now that the Leviathan and Siren were actually clashing, the battlefield might be even more dangerous. That could be the worst possible place for a mere human like Himatsuri-san.

And if she entered a puddle herself, I could not go save her since I had already used up my one-way ticket.

…Was this the end?

As cruel as it was, I could not let Himatsuri-san die. I would make sure she stayed with me.

“Himatsuri-san, listen carefully.”

“Wh-what is it…?”

“I will tell you the full truth of this incident. And a lot of it isn’t going to be easy for you to hear.”

Part 3

“You’re…kidding…?”

As Himatsuri-san listened to my explanation, she held a trembling hand to her mouth.

It must have been hard to believe.

Her eyes widened, but she did not stop me.

“I don’t believe it. Minaki was so kind and she never raised her hand against our cruel father…”

“Being kind and whether or not she used her power are two different issues. In fact, I think it was because she is more human than any of us that she couldn’t abandon you.”

“But…that’s right. What about those parasites? Minaki would never do that to other people!”

“I don’t know about that. Maybe she had some reason to choose those specific people, or maybe she’s lost control.”

Either way…

“If the Leviathan ends this, we might lose any possible chance of removing those Remora parasites. So the only way to save them is to contact the Siren ourselves. Without killing her, of course.”

“Of course we aren’t going to kill her!!”

Himatsuri-san was rightfully angry. Minaki had had her head held down by both of her parents and the circumstances of her birth had prevented her from spreading her wings, so Himatsuri-san must have appeared so bright to her eyes.

“I know what I have to do. I have to dive down there and capture Minaki.”

“You can’t escape the Leviathan like that. That shark is more comfortable in that hellish battlefield than in reality. And the Siren wouldn’t place her base anywhere within the Leviathan’s reach. If we want a chance to speak with her, it would be better to lie in wait at Minaki-san’s hideout in reality and capture her when she appears there.”

“We can’t wait that long!! Minaki could be dying as we speak!!”

“The Leviathan might use you as a hostage!!”

I completely made that up.

I just needed something to prevent Himatsuri-san from succumbing to her emotion and diving into that glowing ocean.

But for some reason, I felt like the puzzle pieces had all clicked into place.

“Minaki-san’s biggest weakness has got to be you, Himatsuri-san! She created that glowing ocean as the game master and the Leviathan intervened as a hacker. If you go where the Leviathan can reach you and keep you from acting, you’ll just be wrapping the noose around the Siren’s neck!!”

…Wasn’t that exactly right?

It was true the Siren had created that place. But Minaki-san had no reason to bring Himatsuri-san there. Not even 1% of one. Meanwhile, the Leviathan had interfered to create exits from that glowing ocean. What if it had used that same interference to bring Himatsuri-san to the battlefield? That was only a plus for the Leviathan!!

That may have been logical.

It may have been the right decision.

But it made me want to scream at the Leviathan:

You piece of shit shark bastard!! You think that shows an understanding of human emotion and you still have the nerve to lecture me on my family affairs!?

“Please understand. The best way to contact and rescue Minaki-san is in reality where the Leviathan can’t interfere. And I doubt my words can reach her, since I’m her enemy. I need your words. There’s no other way!!”

“…But what do we do?”

Himatsuri-san consciously took a deep breath and even I felt a little calmer.

“I know Minaki has to be in this city to spread her song around. But I have no idea where her hideout would be. Do you have any ideas?”

“Did nothing like that come up in your conversations with her? Did she ever mention creating a secret base or having some location with sentimental value to her?”

“…Hmm…”

At times like this, people could prioritize emotion over practicality. I had experienced that a few times with the Bright Cross and Archenemies. Humans were not capable of acting logically when on the verge of death. The closer we got to death, the more we had to face our own souls head-on.

“Himatsuri-san, do you mind if I make copies of all the photos on your smartphone? I’ll delete them once the work is done.”

“Eh? Go ahead. It’s a bit embarrassing, but this isn’t the time for that.”

“Maxwell.”

“Sure.”

I copied all the photos on Himatsuri-san’s phone to my smartphone. There were about 23,000 of them. They were probably a representation of her entire life carried over through several different phones.

“Find any photos with Minaki-san in them and scan her face. Construct an expression palette and rank them from positive to negative. Pay especial attention to anything near the water.”

“Sure.”

“F-facial recognition can read emotions these days!?”

“Nowadays, vending machines commonly include programs that use a camera to track your eyes and expression to determine which products caught your attention. Maxwell.”

“Sure. Task complete. The location that provided the target, Minaki, with the most positive emotions would be the Himatsuri home, but that likely has no bearing on this incident.”

“…Minaki, you idiot…!!”

Himatsuri-san was too overcome with emotion to speak properly. This was not the answer we were looking for, but it may have been necessary.

“When narrowing the search down to only include waterside areas within Kukyou City, I have found a second candidate.”

“What is it?”

“Sure,” said the social media speech bubble. “Kukyou Dam in the mountains. That is most likely where Siren Minaki is hiding.”

Part 4

We had no time.

Himatsuri-san and I left my mom’s apartment and made our way to the mountains on foot. Night had fully fallen. Groups of college students and office workers were heading out for the night, as if to prove that ignorance of this incident was bliss.

“Let’s call a taxi. We won’t make it in time on foot.”

“That sounds great, but it will only take us to the foot of the mountain. Ask them to take us to the dam at this hour and we might get reported to the police for attempting a double suicide.”

Himatsuri-san must have started up a ride-sharing app on her smartphone instead of raising her hand. It apparently used the phone’s GPS signal because a black car smoothly came to a stop in no time.

“Wait, this isn’t a taxi… Is this a hired vehicle!? That costs several times more!!”

“Does it? They’re pretty much the same thing. What’s the difference?”

…She really was from a rich family. I had never ridden something like this before. And didn’t you already need a contract for a hired vehicle like this?

I had been planning to be a man and pay for the ride or at least split the bill…but this crushed any hopes of that. Thinking back, I had almost always used a bicycle or gone on foot when fighting the Bright Cross with Itou Helen. I was apparently part of the petty bourgeois even when my life was on the line.

I nervously climbed into the backseat after Himatsuri-san and the car smoothly left once more.

Then my smartphone vibrated.

“You have received a message from Kukyou University Hospital. Mrs. Amatsu Yurina’s treatment is complete and her situation is stable. There is no risk to her life.”

“I see. That’s good… Wait, what about Erika and Ayumi?”

“I have not received any word of them being injured.”

“Not that. They were left to their own devices after seeing our stepmom injured with no explanation. Maxwell, send them an email immediately! Tell them I know what’s going on with our stepmom and tell them not to go on a rampage!!”

“Sure. …But do not blame me if this has the opposite effect.”

I didn’t care if they got mad at me here. I didn’t want to create any more enemies for isolated Minaki-san. It was hard to say even I was on her side. I certainly couldn’t ignore that she injured my stepmom.

But even so…

Couldn’t the world have been a little kinder to that Siren?

The hired vehicle came to a stop at the foot of the mountain. That would seem a little odd since there were no famous restaurants or sightseeing spots here, but there was no helping that. And perhaps because it was a luxury hired vehicle, the driver did not ask any questions.

We got out of the car.

A while after it drove off, Himatsuri-san asked me a question.

“Could you tell a difference in how the ride felt?”

“To be honest, no.”

We laughed together and then looked to the mountain covered in darkness. I had seen more than enough of it for a lifetime and it felt different again from when we visited that inn before. It was a bizarre scene that I never would have seen in a normal life. My spine tingled from the threat of nature. It was different from the fear of an abandoned school or hospital and it was not quite like seeing the sea soaking up the darkness of the night. We were about to go there. And we were nothing but puny humans who had cast off our claws, fangs, and fur.

“Let’s go.”

“Yes.”

We nodded to each other and started up the mountain road. Even if it had been necessary, I had to wonder what the people were thinking when they carved away the mountain slope and covered it in concrete and asphalt. It felt like walking up the road was the same as entering some forbidden area.

It was true the Leviathan might have a hard time targeting us on this artificial reservoir lake cut off from the ocean. But curling up in this darkness all alone seemed like it would be enough to break you.

I glanced over at Himatsuri-san.

I was glad she was with me. If I had been alone, my mind may have been worn down to the breaking point before I reached the reservoir lake.

We walked up that ominous and evil mountain road.

All so we could reach the massive structure that humans had so insolently built.

“I can see it…”

Himatsuri-san sounded as worn down as I felt.

We saw the straight lines of something artificial mixed in with the curves of nature. It felt like an indescribable blasphemy. The people who had seen it through to completion must have had iron wills. It was beyond me how they had not broken partway through.

“…But where in the reservoir lake is Minaki-san?”

The reservoir lake was quite large. One trip around the perimeter would make for a light jog.

“Maxwell, what about the dam itself?”

“It is always a possibility, but it would not be very realistic. Dams are as serious a target for terrorists as airports and TV stations, so they are made with a high level of security. They are not conducive to infiltrating from the outside.”

“Then it would be a structure near the reservoir lake. Search for deserted mountain cabins or campgrounds.”

“Sure. Including grill stations and agricultural water pump stations, there are 43 in all. Of those, 19 meet the minimum requirement for living there.”

“No, the Siren should be able to freely take materials and food from the glowing ocean. We can ignore the need for water, food, a bath, and a bathroom. Rerun the search while focusing exclusively on whether or not it provides shelter.”

“Sure. There are 25.”

“25 minus 19. If she was trying to trick us, she’ll be in one of the 6 you just added. But a runaway would be starved for information. The battlefield has no power and you couldn’t access reality’s news from there anyway. Plus, the signal isn’t going to be great in the mountains. Check the support situation.”

“Sure. Based on the service area map from each company, 2 of the 6 would not receive TV or radio signals due to the high-voltage lines of a transmission tower. The geographic conditions for 3 would leave them unable to connect to the internet. A cellphone reliant on the communication towers would receive no signal.”

“Then there’s just the 1 that has both TV and the internet.”

We followed Maxwell’s directions to a villa built by a rich person who liked hunting. They had built it outside of the general villa area, so they must not have expected the others to accept a hobby that used real guns. However, they only visited it a few times a year, so it was usually abandoned. If you could avoid the home security sensors and the manager who came to clean the place once a month, it was yours to do with as you wished.

“If they only use it a few times a year, they wouldn’t bother stocking food there. That would be why it wasn’t on the initial search.”

“What a careless location,” said Himatsuri-san. “One reason villas tend to be built together is to share the cost of keeping guards stationed there. The owner is probably trying to lure criminals in.”

“?”

“If it’s self-defense, you’re allowed to shoot, even if it’s a fellow human being. They spice up their life by dreaming of the day it finally happens.”

That sent a chill down my spine. I had thought I had seen enough cruelty for a lifetime with the Bright Cross.

And that was exactly where we were going. We were so deep in the mountains that our connection with Maxwell could be lost at any time. We could shout, but no one would come to look for us. And we could call the police, but we would not hear any sirens for quite a while.

“…Himatsuri-san…”

“You’re a stranger, so you would be in more danger on your own. Without me, I doubt you would be able to talk it out. Also,” said Himatsuri-san on the moonlit lakeside. “This will be fine. As long as this is the Minaki I know.”

Yes, we had to do this.

We would end this here. We would capture Minaki-san the Siren, prevent her from doing anything more, and have her return the Remora-infected people to normal. That would also end the attacks from the Leviathan.

It was all about what was convenient.

A great wall stood in the way of the ideal I had proclaimed. But I had still decided I was doing this, so I had to dive into the danger.

The villa was ostentatiously located on the lakeside and built to look like a log house. It looked like something out of a picture book, but that was what made it seem so unnatural. Were they not afraid of people coming in the middle of the night while making a lot of noise? Or was Himatsuri-san right and they were waiting for the idea to cross some villain’s mind?

I also saw something else unusual.

There was a faint light moving within a second-floor window. It was not the room’s light. It was smaller. It was probably a handheld light or camping lamp.

“There’s someone there.”

“Let’s check it out.”

If we were wrong, the Siren was not there, and a rich person starving for excitement was lying in wait with shotgun in hand, we would get shot the instant we set foot inside. We were crossing the threshold into danger whether we were right or not, but that extra risk sent my heart racing.

“Maxwell, check the status of the home security. If necessary, neutralize it. Without the call center noticing the oddity, of course.”

“No. The sensor on the back door has already been bypassed, so it is effectively neutralized. You can enter through there.”

The villa’s owner wouldn’t do that…I hoped. We exchanged a glance and slowly walked around to the back.

“Maxwell, any light would be risky here. The backlight would stand out, so I’m going to turn it off.”

“Sure. I will vibrate the phone if I detect danger. I will use multiple vibrations like Morse code to inform you what kind of threat is approaching.”

I stuck the smartphone in my pocket and Himatsuri-san and I touched the back door. We slowly turned the knob and pushed the door open so as not to make a noise.

We slipped in through the gap.

I then realized I had screwed up by not having Maxwell determine the internal structure from the architect or construction company’s server. I relied on the moonlight entering from outside and traced along the wall with my fingers to continue on. The mysterious light had been on the second floor, so we first moved to the stairs.

“…”

I felt a tugging on my jacket. Himatsuri-san was trying to tell me something, but I could not even see her expression from this close. Once I squinted and tried to see it, my eyes must have adjusted to the darkness because the surrounding silhouette came into view.

A tall rectangular part of the wall was missing.

Were the stairs through there?

The two of us went there and we did indeed find the stairs leading up. I felt along them and found they were made of wood, so they would probably creak louder than a normal floor. We didn’t have time to worry about looking silly. We used our hands as well as our feet to distribute our weight and slowly climb up.

When I peeked up at the second floor, I saw a short hallway with a few doors on either side. The layout was different from the first floor, so there were no windows and thus no moonlight. A thick darkness hung over the place. I could not tell exactly how many doors there were. I knew how dangerous it was, but I was briefly tempted to rely on my smartphone’s backlight.

But that was what convinced me.

Minaki-san the Siren had succumbed to this darkness as well. That was why she had relied on a light that could be seen from outside.

This darkness was nothing to fear.

It was a weapon that was guiding us.

“…”

Once I thought about using the darkness, my view of the situation changed entirely. I could tell there was just one door with a faint light leaking out from below it. It was not much, but it was as bright as the guiding north star to our darkness-adjusted eyes.

Slowly.

Very slowly, we approached that door. We pressed against the wall on either side. Despite the darkness, words were unnecessary. I nodded and I was confident Himatsuri-san had done the same.

This was her job now.

Only she could do this because of the time she had shared with the girl inside.

I heard her breathing in and out.

And then she spoke.

“M-Minaki…?”

She did not even knock and it was a quiet voice.

A short silence followed.

And then…

Five fingers broke through the center of the door at head height.

Part 5

To be honest, it happened too quickly to react. I fell on my butt and pulled the smartphone from my pocket.

“Himatsuri-san, stand back!!”

“No!! Minaki!!”

The slender arm pulled back in, but then it split the entire door apart. When I watched the door break apart, I felt a fierce tension spiraling in the depth of my gut instead of my mind. Had we been too naïve? Should we have viewed her as the violent Archenemy who had caused such a largescale incident!?

“Maxwell, do your best to simulate the Siren’s next action. Include the predicted vector route and display it over the real scene!”

“No. I have too little information for a simulation.”

Dammit!?

Without Maxwell, I was just a high school boy. Even if she did not specialize in direct combat, she was still an Archenemy. I doubted I could win this fight. Could I at least give Himatsuri-san time to escape…!?

My fear and resolve meant nothing.

With the unsteady light source of the camping lamp dangling from one hand, a silhouette did not hesitate to step out into the hallway. She was holding a light, yet that only emphasized the shadows and made her look more monstrous.

Was this really the person in that photo?

That girl who looked identical to Himatsuri-san?

“Minaki…”

She didn’t have to, but Himatsuri-san still tried speaking to the figure. The Siren moved her eyeballs instead of her head to determine the priority of her prey.

I slowly rose to my feet and picked up a piece of broken wood as quietly as possible. I also started up my smartphone’s camera app and made sure to prepare the flash.

Of course, I could not defeat an Archenemy just by catching her off guard.

But she held a lamp using fire, not a flashlight. I could at least hit her wrist and make her drop that. If I aimed for the confusion as the fire spread at her feet, it was possible I could give Himatsuri-san time to flee.

“What are you doing here, Minaki!?”

I judged the timing. This wasn’t the cleverest plan in the world and she may have already noticed what I held behind my back. The figure took another step toward Himatsuri-san.

“Asami…-chan…?”

Her voice sounded rusty.

But when I heard it, I stopped myself at the last second.

“It’s…really you? Not some disguised assassin…?”

“Minaki, you idiot!!”

Himatsuri-san did not hesitate to hug her. She moved right into the lethal range of the Archenemy’s claws and fangs. Minaki-san was trembling and I could not see her face from my perspective. But when she very slowly hugged Himatsuri-san back, I saw no harmful strength in her arms.

…We had made it in time.

That was all I could conclude. It might not look like much, but this was a miracle we had caused ourselves.

She was not a monster.

Himatsuri-san had proven it.

Part 6

Minaki-san the Siren was more overwhelmed than emotional Himatsuri-san the Human. Minaki-san did react much to anything. Although I had no way of knowing if that was due to the constant tension of her situation or if she had always been gentle.

“Asami-chan, um, are you quite done yet…?”

“Not yet! I won’t let you get away with worrying me like that!! Stay seated there! Why are you perfectly fine when I’m bawling like this!?”

“Ah, ah, ahhh…”

Minaki-san looked troubled, but she showed no sign of forcing matters with her Archenemy strength. In fact, I could see a kind look in her eyes as she looked Himatsuri-san’s way.

I could tell they were family.

No matter how complex their circumstances were, they were definitely blood-related sisters. Social status, their family’s category, and the adults’ issues could not change the fact they were sisters through and through.

“What’s so funny!? Why are both of you smiling!? Taori-san’s boy, you sit yourself down here too!”

“Wahh!?”

When Himatsuri-san focused on me, the pressure on Minaki-san lessened just a little. It looked like it was about time, so I got down to business with Minaki-san.

“About the Remoras…”

“Right.”

“When did you two get on the same wavelength!?” protested Himatsuri-san. “Why am I the only one left out!?”

…I began to wonder if those sisters had chugged a bottle of beer when I wasn’t looking, but continuing on like nothing had happened was a talent of mine!!

“I only asked everyone to search out and eliminate people connected to Absolute Noah,” said Minaki-san. “The list of names I had was horribly incomplete and, looking back, it might have been a decoy list left for someone like me to find.”

“Yes, it is hard to say. Not even I know how many people my stepmother has hidden in this city.”

“Oh, there’s no need to be all polite.”

“When you look like twins, it’s hard to know how to approach you. This way is easier.”

Himatsuri-san had said she was her younger sister, but she seemed older than me either way.

“Now, when you say ‘eliminate’, what do you mean? …Like kill them?”

“This might be hard to hear.”

“Go ahead.”

“Instead of just killing them, it causes a greater panic and more damage to keep them alive and have them infiltrate the organization. From what I’ve heard, Absolute Noah isn’t the friendliest environment, so I thought it would be pretty fragile if you made some internal cracks. Having them bring out some secret documents would have been best, but even if they were caught, it would still have everyone there suspecting everyone else.”

Meanwhile, Himatsuri-san puffed her cheeks out like a child.

“…I haven’t said anything this whole time.”

“You’re free to speak whenever you want. So what is it?”

“It’s all you two! Just so you know, love at first sight always ends in failure. And I won’t let my little sister go through that!!”

“Since when were so adorable!? Did you mentally revert to childhood!?”

“Ah ha ha. Onee-chan, um, always stays right by my side when we’re together.”

If she was always like this, it would have to be exhausting. She probably had her reasons, but it may have been for the best that they only met twice a year.

Anyway…

“Let’s just leave the clingy sister to her jealousy… Now for the real issue here: do you know how to remove the Remoras from the infected people?”

A yes or a no here would change things dramatically. And if it was no, I would never be able to forgive her for what she had done.

“About that…”

But Minaki-san looked troubled.

“The Remoras are Archenemies that attach to the hulls of ships and keep them from moving.”

“What about it?”

“If they just kept doing that, they would starve and die along with the ship. That’s why they’re made to attach and detach, like an on and off switch.”

Some people would see that as giving up too soon and others would see it as a highly convenient biological weapon.

To me, this sounded like history’s most horrific biological weapon. You could think about what to do after spreading it around the world and you could make course corrections if it did not spread the way you wanted. Plus, there was no vaccine or antibodies for it. It simply got inside the body, attached its suckers, and controlled the host, so even if someone was freed, they could always be infected again.

“But the Remoras aren’t listening to me.”

“What?”

“It’s true there were people who were in the way if I was to secretly build a foothold in Kukyou City and it’s true I ordered to have them attacked. I won’t deny that. I intended to release them once I was done, but none of them will switch off…”

We had no way of immediately determining if that was true or not. But it was true that we had not known until now why exactly the Siren had infected the city’s people with the Remoras.

“First the Leviathan, then the Siren, and now a Remora rebellion?”

“Hmm, I’m not sure.” Minaki-san placed her index finger on her slender chin and looked up at the dark ceiling. “I feel like it all got so much more confusing once Leviathan-sama arrived.”

“?”

“That duplicated the chain of command. We had left the main group, but Leviathan-sama is still the lord of the ocean. So when they’re nearby, there’s a good chance the Remoras don’t know whose orders to obey and end up doing nothing.”

“…Are you kidding?”

But thinking about it, would the Leviathan show any concern for the Remora-infected people when it was so focused bringing death to the rebellious Siren?

And weren’t the Remoras parasites that attached to the Leviathan’s body? I had heard that directly from the Leviathan.

But wouldn’t it be able to use that?

If they kept doing damage to my stepmom’s organization, wouldn’t Absolute Noah strengthen their forces and attack the Siren for self-defense and revenge?

The Leviathan was the strongest on the sunken battlefield, but it would have a hard time reaching these inland mountains. And the same would be true of the Mermaids, Lorelei, and other marine Archenemies under its command.

So it was the Leviathan who would have gained from forces that could fight on land.

Had that bastard pretended to be falsely accused to throw oil on the fire!?

“Goddamn that shark!!”

“No, wait. I’m just guessing. I have no real proof. Leviathan-sama might not be doing it on purpose and it might be something else entirely. It is entirely possible this is just the Remoras rebelling.”

“Then answer me this,” I cut in. “My stepmom, Amatsu Yurina, who you know as Archenemy Lilith, came back from the glowing ocean injured. I didn’t see what happened, so tell me. …Who was it that hurt her?”

“The Remora-infected…people.”

“Then was that something you ordered them to do? Did you tell them to kill my stepmom to carry out your objective?”

“No. I came here to attack Absolute Noah until they had to reveal their information on the Calamity. Then I could use that to search for a way of avoiding it other than their ark. Killing the person with the most information would threaten that and we could never work out a compromise if I angered them too much. I would never target someone that important. Even abducting her to get her to talk would have been too dangerous.”

That left only one answer.

Someone had taken over the Remora’s chain of command, pretended to be an ally, and secretly ordered them to attack my stepmom. And on that flooded battlefield, my stepmom would have relied on that demon lord who was an old acquaintance and powerful in the water. Rescuing me without my knowledge would have helped build up her trust.

In other words, it had used me to bring down my stepmom’s guard and then had her attacked while she thought she was safe on its back.

“I’m going to tear that shark bastard’s stomach open and drag out tons of caviar…!!”

“Calm down! And the old texts say Leviathan-sama is female, so that’s really not funny!!”

“Then the fin! I’ll chop off that giant-ass fin and make a soup full of collagen!!”

“That sounds lovely, but please wait!!”

Minaki-san frantically waved her hands around to get me to cool down.

“B-besides, what does Leviathan-sama gain by attacking Lilith…no, Absolute Noah?”

“The individual Remoras don’t gain anything either, do they?”

“Uuh…”

“And my stepmom already gave a reason for the Leviathan to oppose Lilith.”

This wasn’t something I could brag about.

In fact, I was kicking myself for not thinking about it earlier.

“I thought it was a harmless possibility once I learned my stepmom had only used it as a bluff to trick me, but the Leviathan hadn’t forgotten.”

“What is it?”

“There are different theories of which demons are in control of which of the Seven Deadly Sins, but Lilith and the Leviathan both control one. I think my stepmom had sloth and the Leviathan had envy. But since the number of demons reaches the double digits with only seven seats, they’re all lined up there without any clear decisions. If that hurt the Leviathan’s pride, it might want to knock my stepmom out of the running or even just fight her head on.”

Conveniently enough, both Lilith and the Leviathan led organizations. And the Leviathan’s had been created to take on the Bright Cross which could be tied to my stepmom.

“That shark was opposed to her from the very beginning. If I hadn’t done it first, the Leviathan might have started a war. Had he prepared an organization that matched my stepmom’s format so he could challenge her to chivalrous single-combat in the very end? Did he think she had declared war on him when the lowly Bright Cross attacked him?”

It was true my stepmom was taking on the world as a leader of Absolute Noah, but she was driven by a desire to ensure her precious family had a spot on the ark. She no longer had any interest in her authority and reputation as a demon, but the Leviathan’s rivalry had still burned bright.

The Leviathan was the master of envy.

…It sounded silly, but this may have been the obvious conclusion.

“We finally have the whole picture.”

I felt like we had gone around in a circle, but that meant the final diagram was quite simple.

Our enemy was the Leviathan.

Take care of that shark, and this would all be over.

[Self Record] Criminal Motive [Leviathan’s Report]

I have no reason.

If I had to give one, I would simply say this is in my nature.

Chapter 6

Part 1

The date had changed.

Their charge would be complete. I could be dragged into their battlefield from a puddle at any time.

“Maxwell, deactivate the alarm.”

“Sure.”

And I was headed to the aquarium in the harbor sightseeing district’s shopping area on my own. It was of course closed by now, but that didn’t matter. I used Maxwell to knock out the sensors and cameras before setting foot inside. I just hoped everything went according to plan.

“I know the security guards’ patrol route, but I cannot predict the actions of the Remora infected. Be careful.”

“Right.”

Thinking back, the Leviathan’s interference had fully stopped Tanabe-san here. Both him and the Remoras coming from his eyes and nose.

Minaki-san was right. The Leviathan had a greater control over the Remoras. And if she had had the Leviathan’s support, my stepmom would not have been attacked by the infected while she searched that glowing ocean for hours. They could have been stopped at any time.

“…I’ll turn that bastard into a fish dumpling hotpot…”

“Are you irritated because you are hungry?” asked Maxwell.

We released the electronic lock and I entered the building. I walked between the dark, unlit tanks and made my way to the staff only door. I glimpsed security guards a few times, but they were fortunately on their usual patrol route. That didn’t prove they weren’t infected with Remoras, though.

I was blinded as soon as I opened the door. The staff only area had its lights on.

“…Curse this public facility. They’re wasting money and power.”

The light could be seen as a positive or a negative, but I didn’t actually know what kind of eyesight the Remora infected had. It would be silly if I thought the darkness was aiding me, but they could actually see in the dark like a cat. I had to use this to my advantage.

“User.”

“I know.”

I had been fidgeting with something in my hands, but now I placed it over my head. It was an open-face helmet I had bought at a 24-hour discount shop. A really cheap one.

After stepping through another door, I found that giant tank.

“Leviathan.”

It was calmly swimming there. It must have been quite pleased with itself for manipulating us puny humans like that. Probably felt superhuman.

When it came to thoughts and cunning, that may have been true.

But it failed miserably when it comes to human emotion. There was none of the familial love found in my stepmom or Minaki-san even though they were Archenemies as well.

This shark only understood one part of humans: the negative emotion of envy.

It must have tried to speak to me a few times because the Leviathan turned to face me.

But it had to have noticed something was wrong.

I couldn’t hear any kind of voice.

“You can no longer control me.”

I tapped on the temple of the helmet.

“You control the brain using a different method than the Siren. It was a pulse, right? This thing is cheap, but I melted down a fishing sinker and covered the inside with a thin layer of lead. I don’t know if you use microwaves or X-rays, but they won’t reach me.”

And there was no need for conversation.

I just had to get my words through. Anyone could declare war.

“…You know why I’m here, don’t you? You hurt my stepmom, used Minaki-san, stole control of the Remoras, and used the city’s people as hostages. It’s time you paid for that.”

The Leviathan moved a bit away from the tank’s glass. But not because it was not willing to listen. Was it going to build up speed to break the glass? Did it think a human boy or two wouldn’t last long against its teeth?

“Didn’t you hear what I said?”

But for a supposed schemer, you didn’t give this much thought, Leviathan.

I don’t have to stick to a one-on-one battle.

“You control the brain using a different method than the Siren!”

That meant I had no defense against Minaki-san. With the guidance of her ultrasonic song, I could reach that battlefield.

All I had to do was step in a puddle that was already there. And my opponent was already in a tank of water.

“Let’s settle this on the other side, you piece of shit!!”

Part 2

As soon as I plunged into the demon lord’s ocean, I was engulfed by the roaring current.

And the Leviathan had already crashed its 30m body against the reinforced glass wall, shattering it.

At first glance, this seemed like suicide.

In an all-out underwater battle, a human with no gills or flippers had no way of defeating a giant shark.

…Or so you might think.

This was no accident. I had intentionally challenged the Leviathan to a fight in this setup!

“Cough!!”

A salty flavor made it through my tightly-closed lips and my eyes hurt like thin needles were pricking them.

The Leviathan would not have prepared a “today’s exit” door this time. But I had asked Minaki-san the Siren to prepare an exit herself. Specifically, the closest door, the one I had used to enter the room. It was glowing blue. I could survive as long as I passed through there!!

The water roared.

That great mass stirred up the water. It twisted nature to its will and perfectly aimed at me. I would be killed instantly in a straight-line chase. But a 30m shark could not smoothly pass through the narrow staff passageway. It was like the difference between driving a scooter or a large tractor trailer through a back alley. The shark’s great size meant it had to repeatedly move back and forth to squeeze through.

Meanwhile, I arrived at the door. It opened the other way, so I didn’t have to worry about the water pressure holding it shut.

I escaped in less than a minute.

The Leviathan’s head had to be full of questions, but I had no intention of answering them.

This was a human battle. By the time those questions occurred to it, the battle was 80% over already. That demon lord needed to learn how fearsome proper preparation could be.

I threw open the door.

Part 3

I returned to reality along with a bunch of water.

“Cough! Cough cough!!”

“Wait, are you okay?”

Himatsuri-san frantically ran over to me. According to Minaki-san, the Leviathan and the Siren could only send others to the glowing ocean while in reality. If that was true, Himatsuri-san could approach me safely despite the puddle forming around me.

And since they were here…

“O-okay, here I go. Three, two, one…”

She did not sound nervous, but she was an Archenemy.

With a loud crashing sound, the thick metal double doors were bent and another hit broke the hinges so the doors sank down into the water.

Yes, that was the gate the Leviathan used to get in and out.

“…Its body is 30m long. It doesn’t matter where the ‘today’s exit’ door is if it’s too big to fit through. It would destroy the door that links reality to that blue battlefield as it tried to fit.”

And we had destroyed the reality-side version of the one large gate a giant marine lifeform could pass through. And if it could not use that…

“I can’t choose to kill an Archenemy.” I spat out the words to someone who was not here. “So, lord of the ocean, you can rejoice in your lonely freedom in your eternal prison that takes up an entire world.”

If its influence vanished from reality, control of the Remora-infected people would return to Minaki-san. The Leviathan itself could not harm anyone either. Even if some infected remained in the glowing ocean, they could be collected through exits too small for the giant shark to pass through.

This was checkmate.

It was the perfect ending that matched my ideal.

“That was cruel, user.”

“I won’t deny that.”

But just as the Leviathan had obeyed its desire, I would force my ideal through.

I would not allow any bloodshed.

So I would instead accept all other methods.

We would never meet again.

But that went beyond just me. The Leviathan would never meet any human or Archenemy ever again.

“Let’s head home.”

“Sure.”

Part 4

There is no decision to make. Nothing like that is necessary.

[Self Record] Self Report Regarding the Lost Sea [Leviathan’s Report]

Where am I?

What is this?

What happened? The entire world is here, but no one from that world is here.

Is this the end for me?

I finally rule the world, but everything has left that world?

Ha ha.

No.

This is the how I have always felt! This is the scene I have been watching my entire life!!

I am the strongest.

That is why no one ever loved me. That is why I could never truly fight anyone. I was forbidden from going all out. The world was just too fragile.

That is what I have here.

Eternal loneliness and a never-changing throne. Must you smugly show me what I was had been given from the moment of my birth!?

I hate it.

Yes, I hate it.

But not that a puny and fragile human did this to me.

…If this was to be a historic enough battle to leave me in defeat, you should have told me from the beginning. Then I could have given it my all. That was a great warrior who could provide such a challenge for me, yet I was so inexperienced I overlooked it and lost my chance to thank him. It is that inexperience which I hate…!!

Chapter 7

“Fuguu.”

It was all over and Ayumi, my zombie little sister, was puffing out her cheeks like a blowfish.

“I don’t care about that world crisis or evil demon lord or whatever. When you get down to it, this was you being selfish, Onii-chan. Make sure you make up with mom.”

She was blunt but right. And I did not need Ayumi to tell me that while she dived onto the sofa and kicked her legs around. The kitchen trash was full of empty cup noodle containers. Erika could do housework, but the house seemed to fall apart without my stepmom.

Erika sighed while wearing an adult negligee.

“Well, I bet mom will forgive you for everything once she knows you’re back. …Our family doesn’t have anyone willing to do the thankless task of lecturing you.”

“…Um, Erika? I’m not sitting on the floor here because I’m waiting for a reward. I’m simply afraid of that ‘my, my, eh heh heh’ aura coming from you.”

“But, Onee-chan, you sure came back to life once you knew Onii-chan was coming home. You suddenly took a bath and got dressed up. And after sitting by the wall with your arms around your knees the whole time he was gone.”

“…!?”

As they threw dubious information back and forth, my ordinary life was returning.

The Remora-infected people had been quickly released. They had gone to the police about the small creatures filling their bodies and the flooded battlefield, but the glowing ocean had apparently been especially problematic. Everyone assumed it was a hallucination after taking some kind of drug. Feeling like you have small bugs crawling under your skin is apparently a standard hallucination.

Thanks to that, no one was spreading the story much. Since drug use was viewed so harshly, they were apparently afraid that talking it up too much would actually lead to more people trying it.

No.

According to Minaki-san the Siren, she had been targeting people connected to Absolute Noah who had infiltrated the city. In that case, they may have been afraid of making waves and revealing the existence of their ark.

“…Mom.”

The next day, I visited the hospital afterschool.

My stepmom had been injured on the stomach, but the doctor said she would not have a scar. Perhaps that was thanks to being a great demon lord.

“Here’s some fruit.”

“Couldn’t you bring something with more charm? And my stomach is healing, so eating that would only make it hurt worse.”

What else was I supposed to do? It would look pretty weird if I brought flowers for my extremely young-looking stepmom.

“But since you’re visiting, can I assume our little civil war is over? Are you ready to come back home?”

“No.” I shook my head. “You still haven’t scolded me for it.”

“Silly boy. You’re safe and that’s all I need.”

…That was probably all it had been for her throughout. To a sad extent. To the point that she would make an enemy of 7 billion people.

So I had to say it.

Our ridiculous family fight was over. I was sick of running away from home so I didn’t have to see her anymore. But that did not mean we had resolved our differences.

I would face her.

As someone I had decided was family.

“Mom, I cannot accept what you’re doing.”

“I suppose not. …Who would have thought you could raise your kid too well? It kind of makes me happy, which makes this all the more complicated.”

“And I defeated the Leviathan this time. I’ve proven that even a demon lord in charge of deadly sin can be defeated using the right method.”

“Wait, Satori. What did you do to the Leviathan…?”

We could discuss the details later. There were enough of them to fill a whole novel. But my conclusion had to come first.

“Let’s fight, mom.”

I was irreverent.

This was the result of a shameless human who got in one lucky punch and let it go to his head.

But it had to be here.

Now was the only time. If I didn’t go with it, things would only get worse until it was all over.

“I won’t run from you anymore. I won’t run from Absolute Noah. I won’t run from the Calamity. I’ll give this serious thought and find an answer different from yours. So let’s fight. And I’m not talking about a mere fistfight. I mean a more intellectual, higher level, and – most importantly – more meaningful fight. …To put it simply, let’s fight over who has the best method of overcoming the Calamity.”

My stepmom sighed on the bed. She looked at me like I was a stubborn child.

“…Do you have any idea how many calculations I’ve run?”

“I don’t.”

“…Do you have any idea how much I’ve wished for something else?”

“I have no way of knowing something you haven’t told me.”

Finding an easy happy ending would mean a complete rejection of the path my stepmom had taken, of her rough life, and of the personality created by it. It would be the same as pointing at her and laughing while proving how stupid she was to run headlong toward tragedy when there was such a simple alternative.

So this was a battle.

My stepmom had always prayed for something like this, but she had passed the point of no return by now. It was a choice on another level altogether. Finding that would do far more painful damage than breaking her nose with a fist to the face.

I had to understand that.

And then I had to challenge her to a battle with all due respect.

I had to do it earnestly.

My victory would come with intense pain but I had to believe it would also free her from what bound her.

“…You really are a silly child.”

“I know that.”

“This is going to a thorny road. The more you challenge me, the more you will experience the same pain and suffering as me. And you are a sensitive and fragile human. Are you prepared to be skewered by the same agony that a demon lord could not bear?”

“If it will save my family.”

My stepmom said nothing.

But her face crumpled up.

The Leviathan was the demon lord of envy. That was why it had challenged my stepmom, Lilith of Sloth.

But I feel like this was what the Leviathan could not forgive above all else.

No matter how great an organization it created and no matter how many allies it gathered, it was still a giant shark that was feared by everyone around it.

No matter how hard it tried, it could not create a family.

The Leviathan probably never even considered the possibility that the more it worked at being a demon lord, the more it pushed away what it wanted most. If it had wanted the love of a family, it only had to slothfully abandon its job as a demon lord.

That was why it had gone mad with envy.

My stepmom had done nothing at all and yet had what the Leviathan had failed to obtain after all that effort. That would have created unbearable jealousy.

I had known all that, so I was pretty awful myself for trapping that lonely shark in eternal loneliness.

“…I don’t know what exactly the Calamity is. I only know it’s something frightening that guides humanity to destruction. Everything else has been hidden from me.”

I had to say it myself.

I had to harden my heart, tug on the hand of this person who had stopped moving, and bring them back to the sunlit world.

“So tell me. What is the Calamity? What is this great disaster from which even your group feels the need to flee?”

“Well.”

Finally, my stepmom started to speak.

At long last, she slowly produced the words I most wanted to hear.

We were not mother and son here. We were rivals who saw each other as equals.

“The Calamity is…”

And.

And.

And.

I learned of the despair that would kill the world.

This may have been the true starting line.

Afterword

That was the 5th volume of Vampire Older Sister and Zombie Little Sister.

This is Kamachi Kazuma.

The theme this time was a runaway boy and a giant shark. …It’s weird how seeing those two together makes the shark sound more soothing. They can grow new teeth, they sense their prey with electricity, and they’re covered with parasites like the remora. They have so many interesting traits and then I also made this one seem like the child of a submarine and aircraft carrier.

And the best part of shark horror is to have an important character dragged into the ocean, so while I was thinking about how to take that even further, I came up with the idea of having them dragged elsewhere from any kind of water and then killed.

With him running away from home and wandering, this volume revealed Satori’s uncertainty. He doesn’t want the Archenemies to cry, but he also did not swear to obey them. He wanders back and forth in that precarious balance. He is not a perfect human, so if a gear somewhere had been out of order, he might have become a lot like the Bright Cross. I hope you saw his unstable humanity in the compromise he found while facing the Siren and Leviathan.

Now, this time Satori faced his uncertainty and came up with an answer, even if he still isn’t sure whether it is right or wrong. So I also switched things up with the usual “Final Choice” I add in just for fun. From here, he will finally be facing Absolute Noah…or rather, the Calamity they are trying to fight. What exactly is that end of the world? How will history’s greatest mother-son fight end? I hope you are looking forward to those things.

I give my thanks to the image illustrator Mahaya-san and my editors Miki-san, Anan-san, and Onodera-san. I’ve built up the series quite a bit since the first volume. In the process of looking at the same world from multiple angles and creating new things there, the many illustrations and character roughs came in quite handy. As an example, I never would have come up with the idea for the Siren’s hair without the illustration of Kuroyama Hinoki the Mermaid I based it off of. Thank you very much for your help.

And I give my thanks to the readers. I’ll set it in virtual reality so I can do whatever I want! I know, I’ll use a zombie and a vampire!! This series began with some quick ideas like that, but the next thing I knew, it had grown to the point that a boy was directly confronting the end of the world. It was thanks to all of your support that it managed to grow like that. Thank you yet again.

And I will end this here.

I feel like Maxwell has grown even more than Satori.

-Kamachi Kazuma

?

[Self Record] Calamity [Leviathan’s Report]

I see.

Since this is manmade and not a product of god, this eternity is only temporary.

Come to think of it, if Lilith was that afraid of it, hiding in this makeshift lost sea would not be enough to escape. Once it begins, even this place will sink.

I must reassess the situation.

Diving to the bottom of the sea would not have been enough. I was wrong from the beginning. Lilith must have ignored my organization because she knew we would be destroyed all on our own once the Calamity began. She must have felt like the full-prepared ant viewing the lazy grasshopper.

…Ahh, remembering all this is bringing back that old throb of envy.

She is always so bright and keeps showing off what I do not have. And in a way, she is slothfully ignoring how that makes us feel.

Now, what exactly is the Calamity?

Facing a threat to your life in an empty world is the greatest luxury. Since no one can intrude on this stage of mine, I will take my time to observe and ponder this.

Translator's Notes and References

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