Unlimited Fafnir:Volume 6

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Prologue

The young girl knew many things.

At the age when most people were learning arithmetic, the young girl was playing with complicated equations that even adults had trouble solving.

The girl's tiny head was filled with all sorts of knowledge unknown to children of the same age.

Untold numbers of mathematical theorems, knowledge gained from academic texts or illustrated reference books, languages for communicating with machines—It was impossible to count them all.

However, the solution to the one problem, which the girl truly hoped to solve, eluded her no matter how much time went by.

And again today, the girl was looking up at the white image of someone's broad back.

The girl's father was wearing a lab coat, focused on carrying out some kind of research the whole time.

He always had his back to the girl.

Hence, the girl wanted a method to make him turn his head back.

The girl cried: "Father."

But he did not look back, simply sitting in his chair, staring silently at the computer screen.

Even so, the girl still did not give up, calling him relentlessly.

Fa—

"Shut up and give me some peace and quiet."

However, what the girl received were his cold words.

He scolded the girl angrily without even looking back at her.

The girl trembled in fright. The words reaching her throat were swallowed.

Inside the quiet room, all that could be heard was his tapping on the keyboard.

The girl bit her lower lip hard and held her tears back.

Thus as usual, the girl picked up academic texts and began to read in a corner of the laboratory.

Except that her tears were dripping on the open pages.

The girl did not understand.

Why her father refused to look back at her.

Days like these kept repeating. At some point, the girl no longer spoke.

Because speaking would only incur her father's irritation.

Despite being together clearly every day, she felt lonely.

But one day—The girl suddenly gained "an older sister."

Giving off a tomboyish impression, she smiled cheerfully and greeted the girl.

"I'm Ariella Lu. Nice to meet you, Ren."

Chapter 1 - Silent Genius

Part 1

Midgard was the stronghold in the southern seas where Ds, people capable of generating and using dark matter, were gathered.

Their powers would awaken with the onset of secondary sex characteristics then disappear when they reached maturity. Hence, the majority of Ds were school-age children.

Hence, an academy was established at Midgard for the Ds.

The Academy's campus contained all kinds of facilities. There was also a medical building fully equipped with cutting-edge technology.

A week earlier, I was severely injured in the battle against Yggdrasil and admitted to this medical building for treatment, but—

"Principal... I'm getting sleepy. Can we end this here?"

I—Mononobe Yuu—spoke hesitantly to the blue-eyed blonde who was sitting on the bed, face to face with me.

She looked like a petite girl in her teens but was actually Midgard's chief administrator—Charlotte B. Lord.

Dressed in a loose-fitting lab coat, she looked like she was merely "playing doctor" but she actually had a medical license. She was currently my principal physician to conduct treatment for me.

But after arriving at my room under the pretext of diagnosis, she had already stayed for as long as three hours.

"Wait, be quiet, I'm currently thinking."

The principal furrowed her elegant brow, pursing her pink lips, concentrating on her thoughts. Meanwhile, her gaze was focused on the game of Japanese chess on the board between us.

"I'm basically a hospitalized patient, right? I don't think pulling all-nighters is good for my health."

"I've already healed your wound. Since your body is back in full health, keep me company for a while longer. Okay, try this move!"

Smack, the principal moved her chess piece and looked proudly at me.

Yes, my wound originally required a long time to recover completely, but it was all healed now. I was scheduled to go back to school tomorrow.

This was only possible thanks to a "power" possessed by the principal.

She was the "Gray" Vampire—the dragon that controlled other people by using bodily fluids as a medium.

I heard that she had managed human society from the shadows the whole time, preventing humanity from destroying itself. My left arm, controlled by Yggdrasil, was currently at peace only thanks to the principal's power.

But in exchange, my left arm was no longer under my own control either.

"Unfortunately, it's over. Here, checkmate."

I sighed and used my mobile right hand to place my piece in front of the king.

"What!? I can't believe you used a captured piece. That's way too underhanded! You're under my dominance right now, so don't forget I can read your thoughts if I wanted to, okay? But I faced you fair and square without doing that!"

The principal frantically spoke and pointed at the piece I had moved.

"I can't help it even if you call me underhanded, because that's what rules are like for Japanese chess. And I basically explained in the beginning, right?"

"Hmmmm... Looks like I wasn't listening carefully because I was focused on memorizing how the pieces moved. I never expected these factors absent from international chess... This game is more complicated than I imagined."

Arms crossed before her chest, the principal stared at the ended game in chagrin.

"It might be a bit hard playing the first time when you need to memorize lots of things, but I'm actually not that good at chess. Once you get the rules down, Principal, you'll probably play better than me. Besides, I got totally thrashed in international chess just now... Yawn... Then I'm going to bed."
 I cleared up and prepared to put the chessboard away while yawning, but the principal showed displeasure on her face.

"Hold on, one more game. It's too much of a waste to end things here when I went out of my way to order a Japanese chess set just to play with you."

"Can't we just play again next time? I'll be your opponent any time I'm free."

Rubbing my sleepy eyes, I tried to convince the principal, but she made a sulking look and started to place the pieces.

"How could I sleep without avenging my defeat?"

"You're such a sore loser..."

Given no choice, I arranged the pieces in their starting positions.

Inside the quiet sickroom late at night, the principal and I began a second game of chess.

"But by the way, it really is so similar."

After capturing my pawn, the principal placed the piece in her hand and murmured.

"Similar to what?"

"Not just defeating the enemy but also bringing them over to your own faction to become part of your strength—Don't you find this very similar to our relationship with dragons?"

Prompted by the principal's question, I thought briefly about it.

"—Yeah, we gain the powers of dragons by defeating them. Conversely, if we lose, dragons would turn Ds into their mates... It really is quite similar to chess now that you point it out."

"I know, right? As a result, a single victory in our war would greatly affect the overall development of the situation. Mitsuki Mononobe defeated the 'Purple' Kraken while you defeated 'White' Leviathan. Replicating their powers was conducive to later victories, but—"

Then the principal showed a gloomy expression.

Understanding what troubled her, I lowered my voice and asked:

"...You're thinking about Iris?"
 My classmate, a lively and straightforward girl—Iris Freyja.

During the battle against Yggdrasil, Iris had used Catastrophe without going through the step of dark matter. There was a fundamental difference between Iris generating Catastrophe directly, versus how Mitsuki and I replicated dragons' powers through transmutation. This difference was so great that it might transcend the boundaries of what it meant to be a D—

"Yes, I was wondering this. Suppose Iris Freyja were to change into a dragon, whose side would she take?"

Looking at the opposing chess pieces on the board, the principal spoke with worry.

While moving my piece forward, I looked into the principal's eyes.

"Iris is human. She's not a monster like Basilisk."

Falling unconscious from my severe injury, during my first conversation with the principal after I woke up, I heard that Iris might turn into a dragon, but I could not accept such a suggestion

"Don't make such a scary face, it's just speculation. Although I've conducted thorough physiological exams on her, I haven't found any anomalous changes in her body. As a result, I've no intention of treating her as a dragon."

The principal smiled wryly and shrugged.

"Good to hear that."

I breathed a sigh of relief but the principal made a serious face in response.

"Compared to what you are, how you live is more important. Bluntly stated, whether someone is a dragon or not is totally irrelevant. On the other hand, you should pay more attention to her and don't let her feel troubled by her own existence."

"—I understand."

After I nodded and answered solemnly, the principal relaxed her expression contentedly.

"I've inherited this title of a dragon too... But I choose to stand on your side, to live this kind of life. I've also gained a friend like you, so I'm very satisfied with my current lifestyle."

The principal's smile conveyed her candid joy. Feeling embarrassed, I avoided eye contact.

"T-The pleasure is all mine..."

Perhaps offended by my reaction, the principal pouted unhappily.

"However, could you quit speaking so formally to me? I'm playing games with you as a friend right now, so there's no need to care about hierarchy, okay?"

"Huh? But even if you say that, I..."

Having spent a long time at NIFL, a place with a clear system of hierarchical relationships, I could not help but speak in a reserved manner to superiors. This had become a kind of habit.

"Hmph, you're taking that respectful attitude again. Fine, I've decided! If I beat you at Japanese chess, you're forbidden to use polite speech with me again. Also, you'll use my nickname of Charl."

"H-Hold on. Principal, you're Midgard's chief administrator. If I call you that, what would other people think?"

"No problem, just address me that way when we're alone. Okay—I'm going to get serious now."

The principal put her smile away and moved her chess piece with a smack.

"...Sure, and if I win, you'll give up, right?"

I sighed and advanced my piece as well.

"What are you talking about? I intend to play until I win."

The principal smiled proudly.

I was rendered speechless and realized that I was probably not getting any sleep until the principal won tonight.

Feeling bright light hurting my eyes behind my eyelids, I opened my eyes.

By the time I knew it, it was already morning. White rays of dawn were streaming in through the window, illuminating the sickroom's interior brightly.

I remember playing Japanese chess with the principal last night...

Tracing back my memories, I recalled the previous night's events.

The principal really refused to give up unless she was victorious. Taking advantage of my drowsy consciousness, she won against me in the third game. I could not remember anything after that, so that was probably when I fell asleep.

Trying to move my body, I felt something weird. My right arm seemed inexplicably heavy.

I turned my head right to see the principal's pretty face. She was lying on my right arm, using it as a pillow, and was staring at me with her gemstone-like eyes.

"What a wonderful morning. Sleeping next to someone else's body warmth is kind of nice, actually."

The principal rubbed her cheek against my arm with a comfortable look on her face, greeting me in a gentle tone of voice.

"What... W-Why are you sleeping here, Principal?"

Despite a moment of speechlessness, I still asked.

"Because you fell asleep last night the moment I won. To make sure you keep the promise, I decided to wait until you woke up. Come, we're alone right now. Don't be shy, call me Charl."

The principal leaned herself against me on the bed, rocking me. A fragrant scent was tickling my nose. Making body contact with a supple body, I felt blood rush to my face and ears.

"Y-You're too close. Please move away a bit."

"I refuse. I won't release you until I get my reward for last night's victory, because I won't tolerate you cheating me out of my reward."

The principal grabbed me even more stubbornly. Things were not going to end at this rate.

"...Got it. I'll keep my promise."

I prepared myself and took a deep breath.

"Good, ready any time."

The principal waited excitedly for me to speak.

Meeting the principal's gaze, I spoke like a friend:

"Good morning, Charl."

Instantly, a smile bloomed all over the principal's face.

"Wow, you did it! Excellent, that's more like my friend!"

The principal rubbed my head happily.

While her delicate fingers combed through my hair, I felt both embarrassed and extremely comfortable. With these indescribable feelings, I exhaled.

"Is this enough?"

"Yes, I'm happy now. Since you listened to my unreasonable demand, I must do everything I can for you in return."

The principal straightened her relaxed expression and continued seriously:

"Ever since the giant tree, ostensibly Yggdrasil, appeared in Japan, the interference power affecting you has been increasing. Even I cannot tell how long I can suppress it, so we must find a way to take down Yggdrasil as soon as possible."

"But didn't you say before that defeating Yggdrasil requires wiping out all plant life from the Earth? Or maybe I should put it this way... If such drastic measures are required to defeat it, what exactly is Yggdrasil?"

I posed a question I had not asked before. It was a bit awkward to speak because I had to intentionally avoid using polite language.

"When I controlled you, I sensed Yggdrasil's true nature... But I don't have proof. Currently, I am asking Asgard's laboratory to perform verification and I believe there will be response soon. I'll tell you the details later."

"Asgard... So it's a research facility of the higher-ups."

Asgard was an international organization in charge of dragon-related policies, the superior agency ruling over Midgard and NIFL. Most likely including the principal's true identity, they were privy to many secrets. Otherwise, Asgard would feel suspicious about how the principal was able to obtain information regarding the truth of Yggdrasil.

"Gathered there are the world's most prominent researchers on dragons, countable on one hand. Believe in me and them, rest properly and wait for the time to act."

"—Got it. I'll believe in you, Charl, and bide my time."

Seeing me nod, the principal smiled contentedly.

But at that moment, the sickroom's door opened.

"Mononobe, it's morning already! Have you woken up?"
 Entering the sickroom was the girl whom the principal and I had discussed last night—Iris Freyja.

"Eh...?"

Iris was originally smiling cheerfully, but the moment she saw us, her expression froze instantly.

My classmates from Brynhildr Class were also showing up behind her.

"Nii-san, I heard you were coming back to class starting today, so I came to pick—"

My little sister of no blood relations—Mononobe Mitsuki. Upon seeing the principal lying in bed with me, her entire person froze.

The price for downloading pre-civilization weapons data from Yggdrasil was that I had lost virtually all my memories beyond three years ago. Hence, I did not have my memories from when Mitsuki and I were still family and more often than not, I did not know what she was thinking—But now was an exception.

Her face was red, eyebrows raised and eyes staring in anger. Anyone could tell what Mitsuki's current emotions were.

"N-Nii-san... What on earth are you doing?"

Pointing at me, Mitsuki cried out in a trembling voice.

Entering the room after Mitsuki, the others also questioned me with their faces red.

"Mononobe Yuu! What is the meaning of this!?"

Lisa Highwalker glared at me, her long blonde hair almost about to rise vertically.

"Mononobe-kun and the principal... What did you two do?"

Always reading, never showing much change in expression, Firill Crest was showing a terrifying smile.

"No fair that only the principal gets to do this! Tia wants to sleep with Yuu too!"

The young girl with two red horns on her head—Tia Lightning. Only her reason for being angry was different from the others.

"D-Don't do that, Tia. It's not allowed."

Ariella Lu tried to dissuade Tia. Her ribbon-tied ponytail also jumped.

"Mm!"

Ren Miyazawa also kept nodding, her red hair swaying.

"Wait, t-this is a misunderstanding! Listen to me, all of you!"

I frantically tried to find an excuse, but the principal spoke up as though interrupting me:

"—Hmm, it looks like the Academy's students have caught sight of my unseemliness. Actually, I was locked in an intense battle until late last night. Utterly exhausted, I fell asleep with him like this."

The principal got off the bed nimbly and explained the reason to the group.

But after listening to her, all the girls' faces went even redder.

"A-An intense battle until late last night...?"

Repeating the principal's words in shock, Mitsuki looked like she was getting some kind of weird misunderstanding again.

"I'm a bit sleep-deprived... But since there's business matters to handle today, I need to get back to the principal's office first. Work hard on your studies, everyone."

Ignoring the girls' reactions, the principal walked to the door.

The just before exiting the room, she looked back and smiled proudly at me.

"I'll practice seriously from now on and overwhelm you next time. I'll make you scream. Prepare yourself."

Leaving behind words that could easily cause misunderstandings, the principal left the sickroom.

Left behind, I looked in trepidation at the people gathered.

Tia was staring wide-eyed while the others were red in the face, glaring sharply at me.

"Nii-san... Even though I said that impure relations between students were forbidden, I never expected you to make a move on the principal..."

Seeing Mitsuki's clenched fist shaking nonstop, I shook my head and denied in full force.

"I-It's not like that! Last night, we were only playing—"

But Firill interrogated me in a fierce tone of voice after hearing my explanation.

"You were only playing with the principal? A depraved... adult relationship?"

"Stop thinking in wrong directions! My conscience is totally clear!"

Although I explained as much as I could, thanks to deep misunderstandings, it took me a very long time before I could get the girls to accept my explanations.

Part 2

"Seriously, Nii-san... Why did you not say so earlier if all you were doing was playing Japanese chess?"

Along the way from the medical building to Brynhildr Class, Mitsuki remarked with displeasure.

"No, I already said it who knows how many times, but you won't believe me..."

I sighed in exhaustion.

"B-Because it sounded too much like an excuse... Oh, putting that aside, how are your injuries, Nii-san?"

Mitsuki changed the subject in embarrassment and shifted her gaze to my left arm and abdomen.

I had changed into my uniform with my left arm in a cast. Although it was covered by clothing, my abdomen was also wrapped in bandages.

"Don't worry. Although my left arm might take a while to heal up, I think the abdomen bandages can be taken off soon."

Although to others, it might look like I had suffered grievous injuries, thanks to the principal's ability, my wounds had long recovered.

The cast was a disguise to mask the immobility of my left arm while my abdomen did not actually need bandaging. For those who neither knew about my relationship with Yggdrasil nor about the principal's power, the cover story was that I had suffered a fracture.

"That is a relief, but please do not overexert yourself. Please observe instead of participating in PE and practical classes."

"Got it. Thanks for worrying about me."

"Eh... Oh, yes."

Hearing me thank her, Mitsuki nodded somewhat in surprise, her cheeks turning red faintly.

Maybe the way I was talking did not sound like myself.

It occurred to me—If I saw Mitsuki as family, I might not be thanking so solemnly in this kind of situation. But having lost my memories, of course I could not possibly know the right answer.

"Mitsuki-san, you worry too much. This level of injury is completely nothing seeing as it is Mononobe Yuu."

Lisa touched my cast from the side.

Due to knowing the whole story, she was also clearly aware that my left arm was uninjured.

"Lisa... So Mononobe-kun is actually that reliable in your view?"

However, Firill interpreted Lisa's words differently and interjected in a playful tone of voice.

"What, I never... Uh, after all, since he is the one who rescued my parents from Yggdrasil's evil grasp, I won't regard him as unreliable, but... Umm..."

Blushing, Lisa seemed especially flustered.

Seeing her reaction, Firill smiled.

"And you two have pretended to be a couple before. I'm a bit jealous... that your relationship with Mononobe-kun has gotten so close all at once."

Saying that, Firill leaned in. I could not help but feel flustered from the contact between her voluptuous bust and my elbow.

"H-Hey, Firill?"

"Listen, Mononobe-kun, even for just a moment, play the part of my boyfriend—or rather, play the part of my prince."

Looking at me with a pleading and endearing expression, Firill made such a suggestion.

"Wait, Firill-san! I simply asked him to play the part of my boyfriend out of necessity, but right now, there is no need for him to play a prince."

Before I could answer, Lisa pulled me away from Firill.

"Eh... That's so unfair, Lisa, hogging everything."

"I-It's not unfair! I am simply maintaining public morals on Mitsuki-san's behalf."

Lisa looked away from Firill's glare of dissatisfaction. Her answer sounded like an excuse.

"Y-Yuu! Tia wants Yuu to play husband character too!"

But this time, Tia pounced on me from behind wrapping her arms around my neck, choking me.

"T-Tia, I-I can't breathe..."

"Don't do that, Tia, Mononobe-kun is still injured."

Seeing the situation, Ariella cautioned Tia.

"Oh, sorry! Does it hurt?"

Tia frantically jumped down and apologized to me in worry.

"No, I'm fine, it was just hard to breathe. Just as Lisa said, this level of injury is nothing."

"Thank goodness, but... Tia is unfit to be a wife, failing to consider husband's injury."

Tia breathed a sigh of relief but got depressed.

"I-It's not like that. I'll feel cheerful as long as I can see you lively and energetic, Tia. No one will say you're unfit to be a wife."

I tried my best to console her. Immediately, Tia looked up at me and said as though examining my face:

"Really? Then... You think so too?"

"Eh, well, of course, but I'm just giving an objective opinion—"

Given what I had already said, I could not refute my own words, so I had to nod ambiguously.

"Objective opinion? Tia doesn't get what that means, but Yuu approves of Tia as wife! Then Yuu, let's get married!"

However, my ambiguous answer did not work on Tia. She raised her arms and cheered with a joyful expression.

"W-Wait, those are totally separate things—"

"Not marrying a wife who's not unfit, that would be weird!"

"Maybe you have a point, but..."

Cornered by Tia's logic, I could not help but take a few steps back.

However, just as I was about to be trapped, someone extended a helping hand.

"Tia-chan, please don't make things difficult for Mononobe."

Iris had intervened in Tia's conversation with me. Arms akimbo, she spoke to Tia.

"Muuu—Iris is always getting in Tia's way. So Iris wants to marry Yuu too, right?"

"Ehhh!? I-I..."

Iris instantly blushed to her ears. She secretly glanced at me from the side.

But as though suddenly realizing something in alarm, she looked in Mitsuki's direction then shook her head hastily.

"N-No, it's not like that. Tia-chan, what I mean is you can't get married at your age. If you make a fuss, you'll be a nuisance to Mononobe..."

Iris answered with a suffering look on her face. Seeing her expression, I felt a stabbing pain in my heart.

Iris knew that "the me before I had lost my memories" used to have an engagement promise with Mitsuki. Because I had told Iris that "the real Mononobe Yuu" probably loved Mitsuki the most.

Ever since, Iris always worried about Mitsuki's feelings. Surely, she was considering what would happen after I recovered my memories.

Currently—Iris and I were deeply in love with each other.

However, Iris seemed to have prepared herself for the present state of affairs to be lost eventually in the future.

Hence, I was not confident at all whether these current feelings were legitimate, because I could not be certain whether these feelings might waver.

Thus, in the roughly two months that had passed since Iris and I confessed our feelings to each other after the Basilisk battle, our relationship had not advanced a single step. Neither advancing nor regressing, it simply remained stationary while time continued to flow by.

"Feels like Iris never speaks the truth."

Perhaps sensitively noticing Iris' feelings, Tia grumbled with dissatisfaction.

"N-No! I'm not lying! Right, Ariella?"

"Huh? Well—Tia's age definitely cannot marry. I don't think there's a need to rush to get married. You should enjoy the current life more. There's so many things to do before marriage."

Suddenly called out, Ariella answered in a bit of a dilemma.

"Really!? Then what kinds of things need to be done before marriage?"

"W-Well..."

I did not know what Ariella was thinking of, but she went red and stammered ambiguously.

"Hey Ariella, tell Tia!"

Tia tugged Ariella's arm and begged her to answer.

I felt bad for Ariella but breathed a sigh of relief that the subject of conversation had moved on from me.

Perhaps to escape Tia's questioning, Iris also left us in a hurry, going off on her own. Instantly losing someone to talk to, I looked around me with nothing else to do.

We happened to have reached a connecting corridor between buildings, overlooking the school's courtyard and sports ground.

A pile of abandoned scrap, probably from the school festival, could be seen in a corner of the school.

My classmates and I had prepared and opened a Japanese teahouse for the school festival.

Tragically forced to crossdress, pretending to be a couple in front of Lisa's parents, fighting Yggdrasil's clone—Now that I thought about it, those were two extremely busy days.

And only a week of time had elapsed since then.

While I was immersed in reminiscence, I noticed that just like me, Ren was staring out at the school festival scrap.

She looked especially forlorn from the side of her face. Hesitantly, I tried to ask her:

"Ren, what's wrong?"

"......"

She threw a glance at me but did not say a word.

But that was how she always behaved. Ren always answered briefly with an "mm," typed on a terminal, or responded with silence.

I had never had normal dialogue with Ren so far.

But somehow, I had already grown accustomed to interacting with her without the use of words and language. We were naturally able to achieve communication.

If she responded with silence, it was a signal that she did not wish to broach this subject.

Hence, I did not pry and switched to another topic.

"But anyway, so much happened during the school festival. Ren, did you enjoy yourself?"

"Mm."

This time, she nodded in response.

"What did you find the most fun, Ren?"

Ren thought for a while after hearing my question then typed on her portable terminal and turned the LCD screen towards me.

"—Rossweisse Class' haunted house eh. Yeah, that definitely was a blast."

I read out the words shown on the screen and smiled wryly.

Rossweisse Class was where the youngest Ds in Midgard were gathered. Their haunted house consisted of costumed girls trying to scare visitors, but since all they did was scream and play around, it was not scary at all.

However, simply watching young girls playing around in excitement would bring a smile to one's face—Although it was tiring, I found it to be a fun activity for sure.

"Due to Yggdrasil, the afterparty had to be suspended, but if there's another chance, I'd really like to enjoy thing from start to end completely."

"Mm."

Ren answered in agreement. A bonfire party was originally planned for evening festivities. Without seeing the bonfire, it felt like a proper conclusion was lacking.

"Oh... Now that I think back, there's so many things to do apart from the afterparty. I didn't get to visit all the homerooms, and despite this rare visit from my parents, I didn't even greet them once..."

I sighed heavily.

While I was unconscious after the incident with Major Loki, my parents already left Midgard. Since meeting them directly might expose the fact of my memory loss, in a certain sense, it was quite fortunate.

Even though it was unavoidable, I still could not avoid getting tormented by guilt for feeling "thank goodness" inside.

"......"

This time, Ren responded with silence. However, I got the sense that rather than refusing to answer, she was expressing her empathy for what I felt. The same forlorn expression from earlier surfaced on the side of Ren's face again.

"—Is there someone you want to meet during the school festival, Ren?"

Feeling this inexplicably, I tried to ask her.

Ren's shoulders immediately shook. She looked down as though hesitating on how to answer.

However, it looked like I was not too far off the mark.

I knew nothing about Ren's origins and family background, so I had no idea who she wanted to meet at the school festival, but—

"If you want to see the other person, you'll see them eventually. Don't worry."

I placed my hand on her red hair and encouraged her.

There was no proof but I had a precedent. Mitsuki and I were only able to reunite at Midgard because of the effort she had dedicated towards wanting to see me.

However, Ren kept shaking her head under my palm.

"Oh, sorry."

I thought she hated being touched on the head, so I hastily withdrew my hand.

Ren shook her head again as though saying "that's not what I mean." She typed on her portable terminal then showed me the words.

"...I don't want to see him. I hate that kind of person the most?"

I read out the words on the screen. Ren immediately nodded in confirmation.

"By 'that kind of person'... What kind of person do you mean?"

I asked Ren whom she was referring to.

"..."

However, Ren kept her lips shut tightly without answering the question and looked away.

Evidently, she was not going to say more.

Although Ren's relationship with me had become slightly more harmonious compared to the very beginning, there was still a tall barrier between us.

One day, will I be able to become better friends with her, even to the point of having a dialogue with her?

While thinking this, I glanced sideways at the young redhaired prodigy.

Part 3

The situation changed four days after I resumed attending classes.

"—Twenty-five years ago when the first dragon disaster took place, Japan suffered the most severely as the location where Vritra made its appearance. Although the Greater Tokyo Area was devastated, reconstruction after the fact proceeded quite rapidly because the Japanese delayed resistance and refrained from conducting useless attacks. No signs of the tragedy remain visible anymore. However, other countries chose to fight to the very end. The pollution caused by chemical and nuclear weapons has hampered reconstruction efforts."

During second period, Shinomiya Haruka-sensei was lecturing on modern history.

Her long black ponytail swayed every time she walked back and forth at the lectern.

She was both Midgard's commander and the homeroom teacher of our Brynhildr Class.

"—As you all know, Japan is also the country with the highest incidence of Ds. Hence, during reconstruction, many Asgard facilities were built on reclaimed land along Tokyo Bay's shore. Furthermore, there is a large-scale NIFL base. An important stronghold against dragons, from Tokyo's perspective. The people who promoted the construction of these facilities are Asgard's first leader and Japan's prime minister at the time. This will all be on the exam, so please pay attention. Iris Freyja, given your grades, you don't have the luxury of napping in class, do you?"

"Hwah!? Y-Yes!"

Frequently nodding off to sleep, my neighbor Iris replied frantically at the call of her name.

At this moment, the classroom's door suddenly opened.

"Sorry for interrupting the lesson, but I have an extremely urgent announcement."

Principal Charlotte and her secretary, Mica Stuart-san, showed up. Dressed in a maid uniform as usual, Mica-san was holding a stack of paper.

"Principal, what exactly is the matter?"

Shinomiya-sensei asked with concern.

"—Asgard's First Laboratory in the east has proposed a possibility that might be able to defeat Yggdrasil. To verify the plan's feasibility, they have asked us to send Mononobe Yuu to assist them."

"Why does Nii-san have to go..."

Mitsuki asked. All eyes gathered upon me.

Seeing everyone's reactions, the principal added to her explanation.

"There is something you have not been informed yet... After defeating Hraesvelgr, Mononobe Yuu gained the ability to replicate Ether Wind using dark matter. When fighting Yggdrasil, that Ether Wind might come in handy."

"What!? When exactly—"

Mitsuki glared at me. Her face seemed to be saying: Why did you not tell me?

"Don't blame him, because during the process of verification experiments, I warned him he must neither disclose the fact nor carelessly generate Ether Wind."

The principal smiled wryly and appeased Mitsuki.

"—In that case, Principal, do you intend to accept their request?"

Shinomiya-sensei went back to the main topic and asked the principal.

"Yes, not just Mononobe Yuu. I intend to send all members of Brynhildr Class to head forth as the Dragon Subjugation Squad. Once it is known that the plan is feasible, you will go directly to strike Yggdrasil. Of course, I will send additional personnel when the time comes."

After the principal replied, Mica-san, who had been standing on the side, walked up instantly.

"These are letters of instructions issued to all of you. Please accompany them as the commanding officer, Haruka-san."

Mica-san distributed the papers in her hand to us. Written on them were orders dispatching us to the Asgard laboratory in Japan, authorizing us to leave Midgard temporarily.

"Instant departure...? Isn't this too rushed?"

After reading the letter of instructions, Shinomiya-sensei frowned.

"If a means to defeat Yggdrasil exists, then it must be carried out as quickly as possible. The Yggdrasil that has appeared on Aokigahara is growing bigger day by day. The range of mechanical anomaly is also expanding gradually. I fear that the longer we delay, the more disadvantageous it will be to us."

"Fair enough, but... somehow, I feel that you seem quite anxious—"

Shinomiya-sensei's words conveyed slight worry.

"...Nothing of that sort. Anyway, you will start preparing to head for Japan immediately."

Although the principal denied what Shinomiya-sensei said, I knew she was lying.

She was anxious for my sake. Along with weapons data, Yggdrasil had transmitted something akin to a computer virus to my brain. Once the invasive state increased dramatically, even the principal would be unable to stop Yggdrasil from controlling me.

Hence, Yggdrasil must be defeated as soon as possible.

"—Understood. Everyone, we will return to the dormitories to prepare."

Lisa nodded and called for everyone to move.

"Yes! We must get to Japan earlier!"

Iris concurred with a solemn expression.

Since Lisa and Iris knew about my relationship with Yggdrasil, they probably understood the principal's anxiety.

"I agree... Besides, I cannot allow Nii-san to go alone. I have no objections."

Mitsuki agreed with a serious expression. Firill and Tia also nodded.

"The First Laboratory of the Far East Branch... Don't tell me it's..."

But for some reason, Ariella showed a grave expression and muttered to herself.

"Mm..."

Beside her, Ren also made a complicated expression.

"Ariella and Ren, what's wrong?"

I asked out of curiosity, but Ariella smiled wryly and dodged the question.

"Eh? Oh, nothing much. This has nothing to do with you, Mononobe-kun, so don't mind us."

Ariella replied while putting her hand on Ren's shoulder.

"—Don't worry, Ren, I'll be at your side."

"Mm..."

Hearing her say that, Ren nodded lightly in response.

Although seeing them like that worried me, since Ariella said it had nothing to do with me, I could not pry any further.

"Nii-san, let us return to the dorm too."

"Oh, sure."

Urged by Mitsuki, I left Ariella and Ren.

Japan was the country where Mitsuki an I were born and raised.

But to Ariella and Ren, perhaps it was a place of complicated backstories.

Part 4

Midgard was a remote island located south of Japan.

Compared to Firill's homeland that we visited before—the Principality of Erlia in Europe—it was not that far away from Japan.

Hence, we took a long-distance transport helicopter directly from Midgard to Japan, but—

"Ooh... I have had enough of this."

Lisa remarked irritably inside the cramped helicopter cabin. The propellers were noisy and even sitting next to Lisa, I could barely hear her voice.

With four of us sitting against each side of the wall, we waited quietly to reach our destination.

Sitting on the opposite row of seats, Mitsuki and the others showed weariness on their faces.

Without large windows inside the cabin to offer a view of the outside scenery, there was a strong sense of isolation. The frequent vibrations caused our arms to shake, making it impossible to kill time through reading.

Even so, Firill still tried to read a book in the beginning, but since that would definitely result in airsickness, I confiscated her book for the time being. My decision was probably correct since she had quickly gotten seasick on a ship.

"Last time's helicopter ride was clearly much more comfortable..."

Sitting on my left, Iris said in boredom.

"Because this is a military transport used by NIFL as well. Unlike civilian transports, comfort is not a consideration, but we'll probably get there soon. Iris, Lisa, just hang in there a bit longer."

Checking the time on my portable terminal, I encouraged the two girls.

We should be almost there. I was still part of NIFL not too long ago, so I was already used to this kind of uncomfortable transport. However, it must be quite a harsh experience for Iris and the other girls.

Most likely, the principal prioritized speed above all else despite knowing this. Time might be more pressing than I imagined.

I sighed at the sight of my left arm in the cast.

I must not repeat that mistake ever again.

Looking at Lisa's delicate neck while she was sitting on my right, I warned myself.

Controlled by Yggdrasil, I had strangled Lisa's neck, trying to suffocate her. Had the principal not arrived to the rescue, things might have developed past the point of no return.

"...What is it?"

Noticing my gaze, Lisa asked in puzzlement.

"Oh, nothing much... Umm, your neck—I was worried whether any marks were left behind."

Despite feeling embarrassed, I still answered Lisa.

"You still feel guilty about what happened? I'm fine already. Although the finger marks stayed for a while, they're all gone by now."

Lisa replied in exasperation. Her reply was drowned out by the propeller noise. Apart from me, no one heard her.

"I see, that's good to hear."

I could finally breathe a sigh of relief.

"By the way, just to be clear... Even if marks were left behind, I would not resent you, okay?"

"—I know, because you're so nice, Lisa."

I nodded and smiled wryly but Lisa blushed in embarrassment.

"What!? W-What do you mean by nice? It's not like that, it was simply my own carelessness... You're the one who is nice."

"Huh? Me?"

I was surprised to hear this unexpected response.

"For my sake, you accepted this job to play the part of a couple and even worried this much about me... You are too nice, it's so unfair."

For some reason, Lisa's tone of voice sounded a bit angry.

"No, but playing a couple was part of the deal when you agreed to listen to my troubles, right?"

"Indeed that is true, but even without any terms of exchange, upon seeing me in trouble, you would have agreed to my request either way, right?"

"Well... I guess I would've agreed."

If Lisa really was in trouble, I could not leave her without assistance.

"That is why I'm calling you nice, and because you are such a nice person, I—"

Lisa gazed at me with moistened eyes. Due to the propeller noise, I could not hear what she said at the end.

Then just like that, Lisa rested her head against my shoulder.

"L-Lisa?"

Feeling my heart rate rise, I called her name.

"I feel a bit sleepy. Lend me your shoulder."

"You can sleep in this kind of noise?"

"Indeed, as long as I have my lover's body warmth."

Lisa smiled gently and closed her eyes.

"What—"

"Just kidding."

With her eyes closed, Lisa replied with laughter in her words.

Then she really slept peacefully for real.

Next, someone tugged my clothing from the left side.

I looked over to meet gazes with the pouting Iris.

"What are you and Lisa-chan talking about?"

"U-Umm... Nothing important."

Discussing whether I was nice or not—This sounded too embarrassing, I could not say it out.

"Hmph... Mononobe, you really seem like a real couple with Lisa-chan."

Iris made a jealous look. Then looking at Lisa who was sleeping on my shoulder, she leaned against my other shoulder too.

"Hey, Iris?"

"I'm sleeping too, Mononobe, so don't move."

Saying that, Iris closed her eyes.

With Iris and Lisa leaning against me on both sides, I could not move. Giving up, I served obediently as their pillow.

But suddenly feeling gazes from the front, I looked up.

Seated opposite to us were Mitsuki, Tia and Firill, glaring coldly in my direction.

Although they were showing scary expressions on their faces and seemed to be saying something, I could not hear them due to the propeller noise.

"T-This can't be helped..."

I knew my voice could not reach them but still defended myself and stiffly avoided their gazes.

Ignoring us, Ren and Ariella simply stared into space with frozen expressions.

It was roughly half an hour later when an internal line announced that we had reached the destination.

The helicopter landed on a helipad on the roof of a high-rise building somewhere.

Ending the long journey, we dragged our weary footsteps and got off the helicopter. It was currently 10pm at night. Since the longitude here was similar to Midgard's, there was virtually no time difference.

This was probably the Asgard laboratory located in the Tokyo Bay area. Rows of undecorated pure white buildings surrounded this building, reminiscent of a hospital.

The helicopter instantly flew away after we disembarked. According to Shinomiya-sensei, it was apparently flying to a nearby NIFL base to refuel.

"Kyah!"

A strong gust of wind blew, causing Iris to hold down her hair. Compared to Midgard, the air temperature was much lower, but not to the point of chilliness. My sense of seasons had numbed due to being on a tropical island, but now that it was September, Japan was entering autumn.

The sun had already set in the west. Illuminated by bright streetlights the sky showed a murky purple-red hue. With almost no stars visible, there was only the moon hanging high in night sky with the occasional aircraft lights crossing back and forth. The scenery on the shore was hidden behind deep darkness.

But just by turning my gaze inland, I was instantly greeted by a magnificent scenery of the night. Red lights flashed on the roofs of high-rise buildings. Countless dots of light leaked out from windows, decorating the brightness of urban areas. Rows of connected lights were surely headlights from cars driving on highways.

—This is Tokyo.

My hometown was farther inland. Besides, I had already lost all memories prior to three years ago, so I had no recollection of this scenery, but for some reason, a hint of emotion resembling nostalgia flashed across my heart.

"I only visited Tokyo a few times when I was young, but even so, there is this feeling like returning to my hometown."

Mitsuki seemed to be feeling similar emotions while she remarked with a wry smile.

"Well, it's because we've already left Japan for three years. We'll still feel this way even if it's not a city where we lived."

While looking out at the stars twinkling on the ground, powered by electricity, I concurred with Mitsuki.

In contrast to the city center's dazzling brightness, the reclaimed land on shore was only sparsely illuminated. Many facilities were probably deserted during the night.

"Tia is so happy to come to the country where Yuu was born!"

Tia was originally feeble when she first got off the helicopter, but had recovered her vitality now, bouncing around energetically.

"But by the way... No one came out to receive us."

Lisa looked around. Her long blonde hair was fluttering in the strong gust of evening breeze.

On this roof equipped with a helipad, the only people visible were Shinomiya-sensei and the students of Brynhildr Class.

"Do we have to enter on our own?"

Firill pointed at the stairwell leading to the building's interior.

However, Shinomiya-sensei shook her head.

"No, they said someone will lead the way when I contacted them from the helicopter. Let's wait a while longer."

"...Who will it be?"

Ariella commented quietly.

Ren clutched Ariella's clothing tightly, showing an even more nervous expression than on the helicopter.

Then the stairwell's door finally opened and a man in a lab coat jogged over to us.

"Oh my, sorry about that. I'm late because there was a bit of work I had to finish."

The man scratched his messy hair apologetically, his stubble-covered face smiling.

Ren's expression became stiff the moment he appeared. I did not miss this change.

"I knew it..."

Ariella gnashed her teeth and glared at him sharply. She was giving off aggressive emotions akin to killing intent, causing the mood to tense up.

—Was this someone they knew?

I was intrigued by Ren and Ariella's reactions.

"No, thank you for taking time out of your busy schedule to receive us. I am Shinomiya Haruka, Midgard's commander and their homeroom teacher. As the leader of the group this time, I am accompanying these students, Mononobe Yuu most of all."

Shinomiya-sensei greeted and extended her hand to the man.

"I am Miyazawa Kenya, the director of this laboratory. Nice to meet you."

Then man introduced himself and shook hands with Shinomiya-sensei.

Miyazawa, the same family name as Ren. Since it was not a rare name, it could be coincidence, but Ren and Ariella's reactions did not seem to be directed towards someone they were meeting for the first time.

Also, I seemed to have heard the name Miyazawa Kenya somewhere before...

"Miyazawa Kenya... Is that not the author of the paper on Ether Wind? If that is the case..."

Mitsuki asked in surprise then glanced in Ren's direction.

Her words prompted me to remember.

In the initial battle against "Yellow" Hraesvelgr, no attacks worked. In order to find a strategy to break through the impasse, Mitsuki had found a paper on Ether Wind written by someone named Miyazawa Kenya.

"Yes, I am. And you are?"

"Forgive me for the late introduction. I am Mononobe Mitsuki, captain of the Dragon Subjugation Squad."

Mitsuki lowered her head and bowed, greeting him.

"Mononobe Mitsuki... I see, you are the one with antimatter... I remember you called me during the battle against Hraesvelgr, but I only heard about it after the fact. Unfortunately, due to the timing, I could not answer your call. My utmost apologies."

"No, not at all... The paper alone was enough to inspire me greatly."

"I am very happy to hear that. Since you are here, that means... The girl who can use 'Catastrophe' is present too?"

Miyazawa Kenya swept his gaze over us after saying that.

"—Oh, that would be me."

Iris timidly raised her hand.

"Wow, what unexpected fortune. If possible, may I collect some data?"

"Eh... Well, if there's time."

Miyazawa Kenya's eyes shone with excitement. Intimidated by him, Iris answered vaguely.

"Then you have my thanks. Next—Mononobe Yuu and Tia Lightning, I presume?"

This time, Miyazawa Kenya turned his gaze to Tia and me and confirmed with us.

"You know about us?"

Seeing subtly different emotions in his eyes compared to earlier, I asked with concern.

"Although I don't know your faces, I could tell at a glance. I've always wanted to see you, the only male D and the one who successfully replicated 'Antigravity' and 'Ether Wind,' as well as the girl who was given horns through biogenic transmutation."

He leaned towards us in excitement.

"This man... feels so scary."

Frightened by his forcefulness, Tia hid behind my back.

"Oh sorry, I'm a bit overexcited. But I strongly hope you could assist in my research. Especially your Ether Wind, which might turn out to be a trump card for opposing Yggdrasil."

He stared at me and said.

"Well, that's what we came here for, but why Ether Wind—"

"I'll explain that in detail later. First things first, all of you must recover from the fatigue of long-distance travel. I'll take you to your rooms and the dining hall first."

Saying that, Miyazawa Kenya walked to the stairwell. We were just about to follow when a sharp voice pierced the night breeze.

"Wait."

I looked closer to see Ariella glaring at him in fury.

"What is it?"

"...That's all?"

Ariella questioned him in a low voice. Ren stood by Ariella's side with her head down.

"Hmm...? Aren't you Ariella? And Ren too—So you two came as well."

Ren's shoulders shook.

"In other words, you didn't notice until now? How uninterested in us you must be."

Ariella spoke with a strong tone of sarcasm and hostility.

Not knowing the backstory, Iris and the rest of us could only look at one another awkwardly, but Mitsuki and Shinomiya-sensei's faces showed worry instead of a troubled expression. Perhaps the two of them knew something about Miyazawa Kenya's relationship with Ariella and Ren.

"No, it's not like that. I am very happy for a reunion after so long. But why did you come here? You two are not needed this time."

While we watched, he posed this question with an expression on his face as though he found it unbelievable from the bottom of his heart.

Listening with her head bowed, Ren clenched her tiny fist.

"—!"

In that instant, Ariella kicked the ground.

Closing in with merely one step, she swung her fist sharply in a powerful stride.

Mitsuki and the rest of the girls could not react because Ariella's movements were too fast.

Only I made it in time.

Before Ariella's attack aimed at Miyazawa Kenya's face could land, I caught her fist from the side.

A monotonous thud. I felt a wave of numbness on my right palm.

It was a heavy and acute punch. Ariella had exhibited expert martial arts before. She must have trained somewhere before.

"Calm down, Ariella. I don't know the story but violence is not good behavior."

"..."

Ariella gnashed her teeth and withdrew her fist, but she still glared at him.

Staring blankly at Ariella, Miyazawa Kenya asked without any visible surprise:

"—Are we done? Then let me take you all inside."

He turned around and walked to the stairwell.

Without a doubt, Ariella seriously wanted to punch him, but he was completely unfazed.

He could dodge even if I did not intervene—That did not seem to be the case. Judging from the way he walked, he did not seem versed in martial arts.

"Still the same as always... It doesn't mean anything to him. Whether getting beaten by me—or anything to do with Ren."

Ariella muttered in chagrin. Ren approached her and gripped her sleeve tightly.

"What the heck is going on?"

I kept opening and closing my still-numbed right hand while asking Ariella and Ren.

"Oh—Sorry, Mononobe-kun. Thank you for stopping me. I did something pointless and almost caused trouble to everyone."

Ariella smiled wryly and apologized to me.

"No, it's fine..."

I shook my head to tell her I did not mind. Glaring at Miyazawa Kenya's back as he receded into the distance, Ariella spoke:

"Legally speaking, I am his adopted daughter."

"Huh?"

This sudden confession made me speechless.

"And Ren is his daughter by blood, but we are not family with him. Because he has never tried to be a father to Ren."

Ariella continued to glare at his back, speaking in a fierce tone of voice.

Led by Miyazawa Kenya, we entered the lab through the stairwell then took an elevator to the guest rooms on the eighteenth floor—

Based on the elevator display, this building seemed to have twenty floors.

After we settled into our assigned rooms with our luggage, we were taken to the staff dining hall in the lab.

The dining hall seemed to be self-service. Everyone picked their preferred menu items, picked up their food then took a seat, but the atmosphere was very heavy. This atmosphere had hung around ever since Ariella's reveal.

However, only Miyazawa Kenya seemed unfazed. On his own, he continued to explain the interior of the facility.

"This is an ID card for guests, which also serves as a room keycard, so please take the card that corresponds to your own room. This ID card gives access to the eighteenth floor where the guest rooms are, the tenth floor where this dining hall is located, as well as the ground floor's entrance lobby. You can come and go as you like. I basically won't interfere in your movements, because I wouldn't have granted access to anywhere I don't want you to go in the first place."

After saying that, he placed numbered ID cards on the table. The cards were otherwise unadorned.

Once we had picked up our respective cards, he stood up.

"—So, I'm leaving first because I've already eaten. Despite appearances, I'm very busy. I'll come pick you up once you're done with the meal. The battle plan against Yggdrasil will be explained in the conference room after that."

Then without waiting for our answer, he quickly left the dining hall.

Since he was no longer around, the mood eased up somewhat.

Originally glaring at him, Ariella took a deep breath, trying to calm herself.

Due to Ren looking downwards, I could not see her face.

"Then let us begin."

Sitting next to me, Mitsuki announced and we began our meal.

"—So you already knew that Miyazawa Kenya is Ren's father?"

While eating my pork tenderloin cutlet set meal, I quietly asked Mitsuki.

"I already knew beforehand that Ren's father is named Miyazawa Kenya, the scholar who wrote the Ether Wind paper. However, I did not know that he is the director of this lab or about his relationship with Ariella-san and their complicated past."

Mitsuki took a sip of miso soup and answered.

"What happened between him and Ren and Ariella...?"

I whispered while glancing sideways at those two while they were eating.

"You would have to ask them directly."

"I guess you're right... But let's not ask that for the time being."

I smiled wryly to Mitsuki and shook my head.

Ariella had not said a word since what happened earlier. I could tell that she refused to let us pry further. Although Ren was silent as usual, she looked quite unsettled inside.

Given the current mood, trying to get to the bottom of the matter now would truly give one pause.

"Hey Mitsuki-chan, he said we could come and go as we like. Can we go sightseeing?"

As though trying to dispel the heavy atmosphere, Iris asked Mitsuki in a cheerful voice.

"—Shinomiya-sensei, what do you think?"

After thinking briefly, Mitsuki sought Shinomiya-sensei's judgment.

"Please be aware that we are not here for fun. We are currently here to carry out a combat operation against Yggdrasil."

"Y-Yes... I'm sorry."

Hearing Shinomiya-sensei's harsh words, Iris apologized timidly.

"But plans are not yet set. Whether there are days for free time will depend on the schedule. I will consider it based on the situation at the meeting after dinner."

"Oh—That's wonderful! Thank you, Shinomiya-sensei!"

"I'll say this upfront. Don't get your hopes up. It's better if you think of it as a bonus if you do get it."

Although Shinomiya-sensei issued a reminder to the overjoyed Iris, she was also showing signs of a smile on the corners of her lips.

"Nii-san, perhaps we might be able to visit home."

Mitsuki said happily to me.

"Yeah..."

I smiled stiffly and nodded in response.

If I had to be honest, I wanted to avoid it as much as possible due to the risk of my memory loss coming to light if I came into contact with our parents. But I already felt guilty about missing the chance to greet them during the school festival, so I could not refuse.

BOOM!

At this moment, there was a sudden explosion, shaking the entire building. The windows in the dining hall kept vibrating.

"Eh... What happened?"

"An explosion...?"

Firill looked around in puzzlement while Lisa frowned, not knowing what was going on.

"Yuu, look! Outside the window!"

Tia pointed at a window in the dining hall.

Although it was hard to tell from the darkness, there was a plume of dense smoke rising.

The alarm began to sound and the surroundings suddenly got noisy. Armed security guards rushed past in the hallway outside the dining hall.

I stood up from my seat and approached the window. The others followed.

"Looks like... it's no simple fire."

Looking through the window, at the dense smoke rising from the bottom part of the building, I commented.

If this were a fire, they would announce directions and prioritize evacuation. But since they had mobilized armed guards rather than make an announcement, chances were high that this was an external attack, or rather, an invasion.

"Everyone, please remain here on standby before the situation is clarified. But as a precaution against all kinds of situations, materialize your fictional armaments first."

Shinomiya-sensei issued orders to us who were panicking.

"Understood—Brionac!"

Mitsuki instantly responded and created her fictional armament of a bow.

"Caduceus!"

Iris summoned her fictional armament after Mitsuki.

Fictional armament—Siegfried.

I also generated my fiction armament with the appearance of an ornamental gun.

With bated breath, everyone looked out the window.

Next, something suddenly flew out of the dense smoke

It was a shadow rising towards the sky with a tail of red flame—

"Just now... What was that?"

Ariella asked in amazement but no one could answer the question.

Since it happened for such a brief instant, I could not capture the object's appearance clearly either.

But when I looked at the gradually receding red flame, I noticed the object was turning around high in the sky and coming towards us.

"M-Mononobe! It's heading here!"

Iris shook my shoulders in a panic.

"Get away from the window, everyone!"

At Mitsuki's orders, we all kept our distance from the window. Just at that moment, the descending flame stopped outside the window.

Only then did we realize the shadow's true identity.

Wrapped in burning red flames, using them as a means of propulsion to hover in the air was a girl with long fluttering black hair. In addition, there was a blond young man hugging her waist.

I knew their names.

"Kili... and John?"

Overcome with surprise, I called their names.

The black-haired girl was Kili Surtr Muspelheim, the leader of the dragon cult, the Sons of Muspell. At the same time, she was also a D who was deemed a disaster.

The young man was named John Hortensia. Back when I was part of NIFL and the captain of the special forces team named Sleipnir, he was the sniper under my command.

I had heard from my former commanding officer, Major Loki, that John had been abducted in the Principality of Erlia. It turned out that they really were together.

Kili smiled proudly on the other side of the window as soon as she made eye contact with me.

Immediately, the window glass glowed red from heat and melted like candy. Kili's specialty was using dark matter to generate heat. Most likely, she had used high temperature to melt the window glass.

Carrying heat and a burnt smell, the wind blew in through the hole in the melted window glass.

"—Yuu really is here. Your eyes are amazing indeed."

Kili landed on the window frame and said to John.

"Like I said, I cannot possibly miss the captain's figure."

Despite answering proudly, John looked somewhat unimpressive because he was still clinging to Kili's waist. But since he was still suspended in midair, he could not just let go.

"Why are you two here...?"

I asked this question in surprise. Kili turned her gaze to me and smiled.

"We are searching for something. Currently, we are searching every Asgard lab and NIFL base in Japan."

"What... Then you caused the explosion just now?"

"Yes, we made an emergency escape because we were discovered. We were planning to escape just like that, but because Jeanne-chan said she saw you—"

"Hey Kili!"

John cried out frantically.

"...Jeanne-chan?"

Hearing Kili, I frowned in puzzlement.

"Oh sorry, I made a mistake. Speaking of which, your name is John."

Kili spoke suggestively while John gnashed his teeth, looking like he was holding his anger back.

"I'll make you pay later..."

"Fufu, how scary. I won't get it wrong again, so please forgive me—John."

Kili replied gleefully.

Watching their interactions, I felt troubled.

"You two seem to be getting along quite well. I heard from Major Loki you were abducted by Kili... Don't tell me that you're working with Kili voluntarily, John?"

"T-That's a misunderstanding! Captain! This bitch took me away by force... Although it's true I'm currently assisting her, I'm not getting along with her at all—"

Stuttering, John tried to explain the story.

But many footsteps approached from the hallway then security guards rushed into the dining hall.

"Freeze! Surrender now!"

The guards pointed guns at them and issued a warning.

Judging from their equipment, they might be soldiers sent from NIFL. As an international organization, Asgard's premises were not bound by Japanese laws. If necessary, they could shoot without hesitation.

However, even if that was the case, their opponents were not to be underestimated this time.

"Shut up."

Kili glared at them. Instantly, the guns in their hands glowed red-hot and melted like the window just now.

"Uwah!?"

The guards hastily let go and the guns fell to the ground. Then the gunpowder inside exploded.

This was Kili's Muspelheim. By spreading dark matter, too small to be seen by the naked eye, throughout space, this method of fighting allowed her to generate high temperatures at will without any preparatory motion.

"With people in the way, we'll talk next time. Since you're in Japan, there will be other opportunities."

Saying that, Kili stepped on the window frame and jumped into the air.

"H-Hey!"

"Seeya."

Giggling, Kili waved goodbye and flew high in the air, taking John with her.

Even Kili and John had come to Japan...

Watching the trail of red flames, I felt a premonition that an even bigger storm was brewing.

Part 5

"—This place got busy no sooner than you arrived. But to think the intruder was Kili, the leader of the Sons of Muspell... It's such a shame I didn't get to see her."

Saying that, Miyazawa Kenya honestly looked like he found it quite a shame.

We were located at a conference room located on the same floor as the dining hall.

He had arrived immediately after Kili and John had left, then taken us here while we were perplexed by the sudden situation.

"You... want to see Kili? But she's a dangerous character deemed a disaster, you know?"

Surprised by what he said, I asked him.

"I heard she is currently the only D capable of biogenic transmutation. As a research subject, it's very interesting."

He insisted with added emphasis in tone. Ariella glared at him coldly and said to me:

"Mononobe-kun, this guy isn't interested in anything outside of research."

"...Looks like it."

I sighed and decided he and I had different values.

Back to him, Ren was silently looking out the window.

"It's unfortunate that data on Kili could not be obtained, but let's have a chance of pace. Come, please listen to the plan I've conceived to defeat Yggdrasil."

Miyazawa Kenya entered the main topic seriously.

When he operated the laptop by his side, the lights dimmed in the room dimmed and a white screen was lowered from the ceiling.

Shown on it was the image of a giant tree.

"This is an image of the Yggdrasil that has appeared in Aokigahara. Compared to when it was making the Germany-Denmark border its territory, its size is roughly ten times larger. Currently at a height of 5000 meters, it continues to grow."

"5000 meters..."

I could not help but gasp because it was too enormous.

"Although I have my opinions on Yggdrasil's choice of location and the reason for its rapid growth... Let's put that aside for now. The issue here is what kind of existence Yggdrasil is."

After saying that, he switched the image on the screen.

The screen showed the appearance of Yggdrasil that we had fought recently at Midgard. Although its massive body exceeded fifteen meters in height, it was dwarfed by the image we saw earlier. The "mass of vines" produced from my dark matter had expanded to this state after absorbing the fictional armaments of Iris and the other girls.

"To you all, it must have been a huge disaster for Yggdrasil to suddenly appear at Midgard. But thanks to that, we were able to obtain plenty of valuable data. The fact that Yggdrasil relies on the application of electrical interference to tamper with dark matter, this is a new discovery. In addition, the renowned dragon researcher—Principal Charlotte B. Lord—also proposed an extremely interesting 'hypothesis.'"

He spoke quite suggestively.

This so-called "hypothesis proposed by the principal" was probably what she sensed regarding "Yggdrasil's true nature" through her power of dominance.

Miyazawa Kenya was probably one of the few people privy to the principal's true identity. Unless one knew the principal possessed special powers, her hypothesis would become completely baseless.

"We tested that hypothesis and conducted verification. Finally, the full picture of this being known as Yggdrasil has surfaced. It is... the core consciousness of all plants on Earth."

"Core consciousness?"

Hearing this unfamiliar term, I could not help but frown.

But "all plants" reminded me of what I had heard from the principal.

The principal had said: Defeating Yggdrasil requires wiping all plant life off the entire planet.

"For example, Yggdrasil might be considered an operating system... of a biological computer built from a network of all plant life. We have observed that Yggdrasil will transmit weak electrical signals to nearby plants."

We exchanged glances with one another after hearing what he said. Iris and Tia only stared wide-eyed, evidently not understanding, tilting their heads in puzzlement.

The others seemed to grasp the rough principles, but Shinomiya-sensei seemed to disagree and asked a question:

"A computer of plants... That would mean that plant life itself is a dragon. But Midgard has plants to begin with. If Yggdrasil was hostile to us, it should be able to take action earlier, right?"

Immediately, Miyazawa Kenya explained proudly as though praising her question for being a good one.

"Things are not that simple. According to the results of observations, the surrounding plants show no signs of high-level information processing. From this, it can be seen that the giant tree known as Yggdrasil is the only part possessing information processing ability. That true is both the CPU and Yggdrasil's main body. All other plants are like external memory. Hence, one could deduce that only the main body is self-aware and capable of action."

After listening to him, Lisa leaned forward emotionally and spoke:

"Then all we need to do is defeat that main body!?"

She was probably this anxious because she knew about my situation.

However, Miyazawa Kenya shook his head.

"No, Yggdrasil disappeared together with Hekatonkheir on the Germany-Denmark border, but after that, just as you all know, it appeared in Midgard. Then after its defeat, it appeared in Japan like this. Simply destroying the main body does not solve the problem."

"Indeed that is true..."

Lisa's tone weakened while she bit her lip anxiously.

"Yggdrasil's consciousness most likely exists on the network formed by all plants. Even if the CPU, its main body, is destroyed, another plant will simply become the new CPU. Although destroying a mature CPU would definitely weaken Yggdrasil's abilities... The effects might only last for a limited time."

"I-Isn't that the same as saying Yggdrasil cannot be defeated unless all plant life is exterminated!?"

Lisa went pale and exclaimed hoarsely.

Only now did I understand what the principal meant.

"Indeed, the method you described is the only way to eliminate Yggdrasil from the root. But that method is close to impossible. Even if it could be done, humans cannot survive in a world where plants have been eradicated."

Without changing his tone, Miyazawa Kenya calmly told of despairing speculation.

"However, you have an idea, right?"

Calmly listening to his explanations, Firill asked Miyazawa Kenya in a serious tone of voice.

"Yes, of course. That's precisely why I requested for Mononobe Yuu to be sent here."

He turned his gaze towards me and smiled.

"Is there something I can do?"

After listening to all the explanations so far, I did not feel that there was anything I could help.

"Yes, you are currently the only one who can replicate Hraesvelgr's ability—Ether Wind. I believe it will be the key to defeating Yggdrasil."

"Why Ether Wind...?"

Hearing my question of incomprehension, he changed the screen.

Dimming briefly, the screen then showed an image of the Hraesvelgr battle. The picture showed Hraesvelgr enveloped in golden particles as well as us, about to strike it down with anti-dragon armaments... Someone had evidently recorded the battle in detail.

"Mind and body—Living organisms cannot function normally unless both are maintained in healthy states. Since Yggdrasil's physical body cannot be eliminated, just destroy its mind. It is possible as long as we have your Ether Wind and the weapon that penetrated the 'soul coating' surrounding Hraesvelgr."

Miyazawa Kenya pointed at my anti-dragon armament on the image and asserted clearly.

Shinomiya-sensei's eyebrow moved as though she had noticed something. She urged Miyazawa Kenya to continue.

"Director Miyazawa, could you explain in greater detail?"

"It's actually not that hard to understand. The plan itself is very simple. First, obliterate the majority of Yggdrasil's main body, then spread Ether Wind. After that, if Yggdrasil's mind—the soul—materializes, use the weapon that defeated Hraesvelgr to physically destroy Yggdrasil's soul. That's all."

After listening to his explanation, everyone gasped.

If the main body could be switched endlessly, just destroy Yggdrasil's intangible consciousness itself—I believed that this approach was correct in theory, but...

"That method... Will it really work that smoothly? Given Nii-san's dark matter generating capacity, will there be enough Ether Wind to spread around...?"

Mitsuki turned her gaze at me. I smiled wryly at her in return.

"Definitely—my generating capacity is too little."

Converted into mass after transmutation, the amount of dark matter I could generate at a time was roughly ten kilograms. Compared to an average D's capacity of ten tons at least, the paucity of my generating capacity stood in even greater contrast.

Even after hearing such a question, Miyazawa Kenya remained unfazed. Smiling, he said:

"Your worries are very normal. Hence, in order to review whether this plan is feasible or not, I must first collect more detailed data. If possible, it would be best to start immediately."

He looked at me with eyes filled with anticipation. I sensed that his motivation stemmed more strongly from curiosity and his interests as a researcher than for the sake of the battle plan. However, I had no objections to getting started as soon as possible, because based on what the principal had said, time was running out.

"I understand."

"Wow, thank you. If possible, I would also like to have Tia-kun, Mitsuki-kun and Iris-kun's assistance. Although there is no direct relation to the battle plan, the uniqueness you possess might provide breakthroughs to problems."

He thanked me and sought the cooperation of Tia and the others.

"Tia will go along with Yuu!"

"Me too, if Mononobe is going, I'm coming along too..."

Tia and Iris agreed, but Mitsuki looked at Shinomiya-sensei and asked:

"Shinomiya-sensei, what do you think?"

"I will permit it so long as the examinations do not burden the students' bodies or mind. If you intend to conduct suspicious experiments, I will stop you immediately."

Shinomiya-sensei declared to him in a fierce tone of voice.

"I understand. I only need to examine the matter they create and carry out oral interviews. I promise not to use any drugs or touch a single hair of theirs."

He answered in a relaxed tone of voice then stood up.

"Then please follow me. I will take you to the examination room in the research area."

But just as he was about to exit the room, Lisa called to him.

"Excuse me... What about us?"

Lisa, Firill, Ariella and Ren were not named by him just now.

He swept his gaze across them then said in apparent disinterest.

"Oh, I don't particularly need data from you, so you may return to your rooms."

"...!"

Hearing his reply, Ariella gnashed her teeth in anger. Ren kept her head down and did not react. Although I did not know what had happened between him and Ariella and Ren, I could understand that his words had hurt them. Including me, everyone was glaring at him as though condemning him.

"...? What's the matter?"

However, he was not fazed the least. He probably was not even aware that his words had hurt Ariella and Ren.

"—Then we'll be on our way. Let's go, everyone."

Firill spoke to smooth things out. As though to appease Ariella, Lisa placed a hand on her shoulder.

"Ariella-san, Ren-san, let us depart."

Hearing Lisa, Ren nodded lightly.

Thus, Lisa, Firill, Ariella and Ren quietly left the conference room. After that, the rest of us followed Miyazawa Kenya to the research area.

Part 6

Leading us to take the elevator, Miyazawa Kenya swiped his own ID card on the panel. Immediately, all the floor buttons lit up.

Access to different floors by elevator was probably restricted based on each ID card's authority.

He pressed the button for the third floor underground. From what I could see, this building seemed to have five levels underground at most.

After reaching the third floor underground, we walked out of the elevator and looked around. A dark corridor extended into the distance. Apart from faint air conditioning noises, there was no sound at all. It was especially quiet.

"This way please."

He walked in the lead with Shinomiya-sensei, Mitsuki, Tia, Iris and I following in that order.

"It feels a bit scary..."

Feeling an atmosphere different from the dining hall floor, Tia commented uneasily.

"It does feel slightly creepy... Or rather, I would describe this atmosphere as like a hospital at night."

Mitsuki looked down the deserted corridor and remarked.

"So many crossroads. I'll definitely get lost if I came alone."

Iris looked left and right at a set of crossroads, squinting.

"Don't run around randomly, okay? If you end up somewhere weird and the alarm sounds, the guards might come rushing straight away."

"Yeah, in that case—I'll hold on to you, Mononobe."

Iris nodded then paying attention to Mitsuki and the others in front, she hugged my arm.

Feeling my elbow against Iris' soft bosom, my heart rate began to quicken.

"H-Hey."

"If anyone looks back, I'll let go, so please, I want to act like a couple with you, Mononobe."

Iris whispered quietly so that only I could hear, then hugged my arm even more tightly. Feeling my arm sandwiched between those beautifully shaped breasts, my blood rushed to my face. Iris was apparently still bothered by what happened on the helicopter ride.

"—Got it."

I smiled wryly and agreed. Iris then happily leaned her forehead against my shoulder.

Since I must pay attention in front while walking along the corridor, I felt especially nervous.

"This feels so exciting, Mononobe."

Perhaps feeling the same as me, Iris smiled mischievously and whispered softly.

Seeing her like that, I suddenly thought—Speaking of which, if Iris were to be examined as she was now, wouldn't that be bad?

"Iris, after the battle against Yggdrasil, did you ever try using Catastrophe?"

"No, not even once. The principal said it was very dangerous and asked me not to use it on my own."

Iris shook her head so I asked her:

"Iris, do you still remember... how you used Catastrophe?"

"Let me tell you... Honestly, I can't remember at all, because I was in a trance at the time."

Iris drew near my face and answered quietly.

As expected, Iris did not seem to have realized herself that she had used Catastrophe without going through the step of dark matter.

In that case, if the following examinations brought this to light, Iris might feel quite troubled. Moreover, if Asgard were to learn of this truth, it might be very bad.

The principal had said that Iris might become a dragon. If Miyazawa Kenya or Asgard were to see her in the same way, Iris might be in a dangerous position.

"Iris, if that's the case, could you not use Catastrophe during the tests? Because we should obey the principal, Midgard's chief administrator, above all else."

"Oh... I guess that's true. If you didn't remind me, Mononobe, I probably would've wanted to use it. Thank you, Mononobe. Then I won't try a real demonstration."

Although I found the reason a bit contrived, Iris accepted it honestly and thanked me.

I breathed a sigh of relief. Now, Iris' secret would not be leaked.

"—We've arrived. Please enter."

We happened to reach the examination room at this time. Iris and I hastily separated and entered the room at Miyazawa Kenya's urging. Instantly, the smell of antiseptics struck my nose. The plain white room contained many examination devices. There was a spacious room next door separated by glass.

"Then let us hurry and collect data. You'll start first. Please enter the examination room over there and show me Ether Wind."

He pointed at the examination room and looked at me with fervent anticipation like he could not wait. I nodded and entered the room that was isolated by the glass.

Fictional armament—Siegfried.

Then I used my dark matter, which was maintained in the shape of a gun, to transmute Ether Wind.

"Ether Bullet."

Golden particles were shot out as a bullet then exploded.

'Splendid... This is precisely Hraesvelgr's—'

I could hear Miyazawa Kenya's voice through a microphone.

Through the glass, I could see his expression twisting in joy.

His expression gave me a creepy feeling. Indescribable unease surged in my heart.

Following Miyazawa Kenya's instructions, I performed transmutation inside the examination room then answered questions based on the data afterwards. The examination was this simple.

He seemed quite disappointed about Iris refusing to try out Catastrophe, but it could not be helped. Surprisingly, he spent the most time on interviewing Tia.

"—I heard that Kili gave you your horns. Could you tell me in detail what happened before and after that?"

Just as when I used Ether Wind, his eyes displayed a strong desire for exploration while he asked Tia questions. I listened closely because it was also my first time hearing her talk about this topic in detail.

"Umm, she first gave me an injection to prevent pain... Then I felt sleepy. When I woke up, the horns were already there."

"I see... Since anesthetics were required, it meant that the process probably strained you substantially. Did Kili say anything about your horns?"

When he asked that, Tia went "hmm..." for a while.

"Kili said that these horns were for making Tia become a dragon."

"To become a dragon, these words could be interpreted in so many ways. What else... Did she say anything about how these horns should be used, for example?"

"Used... Oh, come to think of it, Kili seems to have said—'We will fight together when you're able to use these horns!' She said that we needed to fight to become real dragons!"

Hearing Tia's answer, his eyes flashed with the light of excitement.

"In other words, your horns are for fighting a certain existence? What exactly is the opponent? Also, what does a 'real dragon' mean?"

Tia shook her head in puzzlement at his additional questions.

"Dunno. When Tia's dragon mark turned red, Kili said 'Since you will become a Basilisk, those horns probably won't be needed'... Apart from that, she refused to say anything more."

"Right, you were targeted by Basilisk initially. In other words, you almost became a dragon, in a manner contrary to Kili's original intent, but because they defeated Basilisk successfully, you are still a D..."

He glanced at us, slightly regretful in tone, as though he felt disappointed that Tia was a ordinary D.

"I guess I must ask Kili if I want to know more. Thank you for your assistance."

Saying that, he ended the questions for Tia.

Since his inquiry of me, Mitsuki and Iris had finished, all examinations concluded here.

The whole thing took roughly an hour.

Things ended earlier than originally expected. I exhaled.

"Then how are the results? After these tests, do you think the previously mentioned plan to strike Yggdrasil is possible to carry out?"

Mitsuki asked him while he was summarizing the results.

"Well, if the original plan were to be followed exactly, success is impossible."

"Eh..."

Seeing him give a negative answer so readily, Mitsuki was speechless for a moment.

"I just confirmed with him earlier. When the soul of the previous King of Erlia manifested due to Hraesvelgr's Ether Wind, its size was roughly the size of a human. In other words, the size of a soul might very well be proportional to the size of the physical body. In that case, the amount of Ether Wind he can create at a time is still not enough."

Miyazawa Kenya looked at me while replying.

"No way... Then what should we do—"

Iris said with melancholy on her face.

"No, I don't think you need to be that pessimistic. If there is a shortage, just add extra supply. You Ds are capable of lending dark matter to one another, aren't you?"

"Oh, that's right! Tia just needs to lend dark matter to Yuu!"

Tia raised her arms and cheered.

Indeed, this problem would be solved just by borrowing dark matter, however—

"Tia, controlling other people's dark matter is very hard. I don't know if I'll be able to do it..."

"Really? I heard that you always borrowed dark matter from others to construct giant weapons..."

Hearing what I said, Miyazawa Kenya asked in disbelief.

"I can't explain it very well... But this is different from the principles of weapon creation. Even if you ask me to try right now, it'll probably fail."

When creating weapons, I performed transmutation according to the data downloaded from Yggdrasil. Due to clear blueprints, it was possible to forcibly filter other people's dark matter through the blueprints.

But when using my own imagination as the base to perform transmutation, there would be ambiguous portions no matter what. If interference from the dark matter lender was added to the mix, the transmutation process would fail.

Lisa had trained in borrowing Ren's dark matter prior to the Basilisk battle, but it was still quite an arduous struggle. This was despite the fact that they had already accumulated vast amounts of dark matter training even before my transfer to the Academy—

"Hmm... But it's not impossible, right? Then all I can do is ask you to do your best. Regarding the prior stage of destroying Yggdrasil's main body, it should be achievable just by using antimatter or Catastrophe, so please do your best for the rest."

He finished as though it was no concern to him, then turned his back to us and started clearing up the examination room.

"Hold on, is there no other way?"

Shinomiya-sensei asked him frantically but he replied without even looking back:

"None. This is the only battle plan I can offer. But if alternatives occur to me during the process of data analysis, I will let you know. Okay—Let me take you back to the elevator."

Switching off the lights in the room, he ushered us to the corridor.

While walking, he still continued to browse our examination records on the tablet on his hand.

He no longer looked at us, simply muttering to himself while walking quickly along the dim corridor. Just as Ariella said, he was only interested in his own research.

Perhaps he was simply using the Yggdrasil matter as an excuse to collect data from us.

"Looks like we can only rely on ourselves for the concrete battle plan."

Mitsuki remarked while staring at Miyazawa Kenya's back.

"Yeah... Can you think of a solution?"

"This will depend you, Nii-san, because the plan is based on Ether Wind and the anti-dragon armament that defeated Hraesvelgr."

Seeing Mitsuki's expression of unease, I smiled wryly in response.

"I'll do everything I can even though I don't know if my power is enough."

Currently, that was all I could say.

But since Yggdrasil was an enemy... I could not use a new anti-dragon armament to reverse the situation as before. If I tried to download new weapons data, Yggdrasil really might try to take over my body this time.

"...You did not say those words this time, Nii-san."

Mitsuki commented with slight incredulity.

"Which words?"

"—Leave everything to me."

I was shocked inside to hear what Mitsuki pointed out.

If the original "Mononobe Yuu" were here, would it be that kind of scene right now...? Or was I feeling uneasy because I could no longer rely on Yggdrasil?

"...I guess I'm a bit afraid. Sorry, I should pull myself together."

Hearing me apologize, Mitsuki smiled for some reason.

"No, it is fine. Nii-san, you should be more afraid, because that reassures me more."

Mitsuki shook her head slowly. She seemed to believe this sincerely.

Part 7

"—We have to do our best on our own. That guy hasn't changed at all. He actually doesn't care about Yggdrasil, I think."

After hearing from Mitsuki what happened at the examination room, Ariella spoked as though spitting.

"...Mm."

Ren also nodded faintly to express agreement.

We were currently on the eighteenth floor of the laboratory, in the guestroom assigned to Mitsuki.

Including Shinomiya-sensei, all nine of us were gathered in the room for a strategizing meeting about how to fight Yggdrasil.

"However, we have already obtained the necessary information. It is also true that what follows is our own job. Hence, let us first consider how to defeat Yggdrasil."

Calming down the furious Ariella and Ren, Mitsuki operated her tablet on a table to display Yggdrasil's image.

Sitting side by side on the single bed, the girls looked at Mitsuki.

It felt quite packed with so many people in a one-person room.

But it would be a pain to ask Miyazawa Kenya to let us use the conference room again, so we made the best of what we had and gathered in Mitsuki's room.

Standing by the window overlooking Tokyo's night scenery, I listened to Mitsuki.

"As things stand currently, eliminating Yggdrasil is almost impossible. Hence, just as Director Miyazawa proposed, instead of targeting Yggdrasil's body, destroying its mind to paralyze it would be the most effective measure. However, there are two serious questions—"

Mitsuki shifted her gaze to me and continued:

"The first is Nii-san's dark matter generating capacity, which is probably insufficient to spread enough Ether Wind to materialize Yggdrasil's soul. The other is that of range."

"Range?"

I frowned, not knowing what she meant. Miyazawa Kenya had not mentioned anything about range.

"It is said that electronics act anomalously in the area around Yggdrasil, most likely due to Yggdrasil's electrical interference. Considering what happened in Midgard, our dark matter will very likely be stolen within that interference range."

"In other words, we cannot get close..."

Mitsuki nodded at Lisa's comment.

"Yes, I intend to request for information regarding the precise interference range. But from what I have seen in reports on television, its current interference range might be around fifteen kilometers or so. Furthermore, Yggdrasil continues to grow, which means that range will expand even farther."

"T-Then that means we must attack from very far away?"

Iris asked frantically.

"Indeed. Yggdrasil is gigantic. Although we could use the same method and have Lisa-san snipe from afar as during the Basilisk battle, Nii-san has to be the one to deliver the fatal blow. Nii-san, are you capable of sniping Yggdrasil from fifteen kilometers away?"

I crossed my arms after hearing Mitsuki's question.

With detailed weapons data in my mind, I considered the specs—

"Noah, which had defeated Hraesvelgr, is not a weapon suitable for sniping, because each shot is not very high in firepower. Destroying a target would require a large number of shells. But striking from as far away as fifteen kilometers is very difficult and would lower the power as well. To be honest... It's very hard."

Mitsuki brought her hand to the side of her mouth and said:

"In that case... We must approach as near as possible. If electrical interference is the only obstacle, we will discuss with Director Miyazawa to try coming up with countermeasures."

Shinomiya-sensei spoke up.

"Let me take charge of this part. Although I am reluctant to owe them favors, I will also attempt to contact NIFL."

"Thank you, Shinomiya-sensei. Then let us focus our attention on solving the other problem."

Mitsuki thanked Shinomiya-sensei and turned her gaze to me again.

"Nii-san, please borrow dark matter from Ren-san and try to construct your fictional armament."

"Huh... Borrow from Ren?"

I looked at Ren in surprise.

"!"

As soon as we made eye contact, Ren instantly hid behind Ariella.

"Indeed, Ren-san's dark matter generating capacity is outstandingly enormous even among us. Even so, it is still unknown whether it is enough to materialize Yggdrasil's soul, but I believe that having Ren-san assist in distributing Ether Wind would be the most suitable."

"—You heard her, right? Can I ask you to assist me?"

I lowered my gaze and asked Ren. Somehow, it felt like interacting with a wild animal.

"Come on, Ren, you're not afraid of Mononobe-kun, right?"

At Ariella's urging, Ren walked over to in front of me.

"......Mm."

Then she nodded hesitantly.

"Great, let's start. Fictional armament—Siegfried."

I constructed my fictional armament of an ornamental gun as usual.

"Mm."

Ren placed her hand on Siegfried's unsteady outline.

As a result, a large amount of Ren's dark matter flowed into the fictional armament all at once.

"Guh..."

The fictional armament expanded and became distorted in shape. Unable to maintain its form, Siegfried turned into black bubbles of dark matter and disintegrated.

"—Looks like it is true what Nii-san said previously about the principles being different from weapon creation."

Observing the entire process, Mitsuki showed a troubled look on her face.

"Yeah, it's very hard after all."

I stared at my empty right hand.

"Unless you can maintain other people's dark matter in the state of a fictional armament, you will not be able to perform transmutation freely. Nii-san, please train with Ren-san to achieve fictional armament creation as quickly as possible."

"Well, even if you say that, I... Is it possible to do that in a short amount of time?"

I understood after an actual attempt. Other people's dark matter would not obey ambiguous orders. Unlike weapon blueprints in the mind, constructing a fictional armament based on imagination alone was extremely difficult.

"In the battle against Basilisk, Lisa-san successfully synchronized with Ren-san in short time, so it should not be impossible."

"That's true now that you mention it. What kind of training did Lisa do at the time?"

I asked her to see if there was some sort of trick.

"Training huh? I did practice repeatedly, but I think your issue concerns the stage before that."

Lisa shrugged and answered as though exasperated by me.

"The stage before that?"

"Dark matter from other people carry their thoughts. You might call them fragments of the mind. If you want to control Ren-san's dark matter, you must first know Ren-san herself."

"Understand Ren..."

I looked at the redhaired girl beside me. I definitely did not know her very well.

"Rather than training, it would be better to say that you and Ren-san are lacking in communication. To help you know each other better—Why don't the two of you go out together and have some fun tomorrow?"

Lisa pondered for a moment then made this suggestion.

"Mmmm!"

But Ren went red in the face and shook her head fiercely.

"Hanging out as a pair immediately is setting the bar too high."

Seeing her like that, Ariella smiled wryly.

"In any case, let us all go out together, whereupon you two can communicate as much as possible in the process, how about that?"

"......Mm."

Ren showed a hesitant look but this time, she nodded in agreement.

"Then it is decided. Is there anywhere you would like to go?"

Prompted by Lisa, Ren took out her portable terminal and typed swiftly.

"Mm."

Ren showed us the terminal.

Two words were displayed.

"Amusement park?"

I read out the words and Ren nodded in confirmation with blushing cheeks.

Chapter 2 - Heart to Heart at a Park

Part 1

Japan was both the place where "Black" Vritra first appeared and also the country where the existence of Ds was first confirmed.

Hence, Japan was akin to a pilgrimage destination for dragon worshipers.

Conversely, to those who rejected dragons and Ds, viewing them with hostility, Japan was also the principal culprit for everything—A cursed land.

And in Japan's capital of Tokyo, people subscribing to both extremes of ideology were gathered, producing many organizations with elements of new age religions.

Conflicts between organizations of dragon worshipers and dragon haters were gradually becoming a significant social problem in Tokyo.

"All idiots."

At a luxury hotel located in the heart of the capital, Kili Surtr Muspelheim was looking coldly across the land from a window of a suite on the top floor.

Inside a vast park near the hotel, two groups of demonstrators had been facing off since morning. This type of conflict between dragon cultists and dragon haters was commonplace recently.

"Whether worshiping dragons or hating dragons, you are clearly nothing more than humans..."

Kili spoke with disdain from the bottom of her heart.

Even though she was revered as a priestess by the Sons of Muspell, a radical cult of dragon worshipers, it did not mean that their beliefs were on the same wavelength.

Kili was simply using them for her own convenience.

All she needed to do was ask and they would prepare a cult-affiliated hotel like this one. Although such loyalty was valuable, it was also ludicrous at the same time.

From an outsider perspective, Kili shifted her gaze away from those squabbling fools and walked over to Jeanne Hortensia who was silently performing maintenance on her firearms in a corner of the room.

"Jeanne-chan, how long are you going to sulk for? Stop being angry."

"......"

Kili spoke gently to her but Jeanne replied with silence.

"If you're angry about me calling you Jeanne-chan in front of Yuu, didn't I apologize already? And even if Yuu finds out you're a girl, what problem will there be?"

Hearing Kili's question, Jeanne lowered her hand in the middle of maintenance.

Putting down the gun on the floor with slightly trembling hands, Jeanne glared angrily at Kili.

"The problem is huge! I established a relationship of trust with the captain as a man. If he found out I'm actually a girl, then all the trust I've accumulated will be gone."

"Will it? Wouldn't Yuu be happier if he found out you're an adorable girl?"

"T-The captain is not that type of weak man! He is stronger, more noble and kinder than anyone, an ideal—"

"Ahhh, stop! Stop! You don't need to say anymore. I've already had enough of your praises for your captain."

Kili interrupted Jeanne irritably.

"You better know it. Please don't insult the captain ever again."

"...Fine fine, Jeanne-chan, you've got such a troublesome personality."

Kili sighed in exasperation.

"You're in no position to criticize me for that."

Jeanne made a sulking look and turned her face away.

"Seriously, you're sulking again. I'll let you meet Yuu again in the near future, happy now?"

Kili appeased Jeanne as though talking to a child.

"Meet the captain...?"

"Yes. I've ordered the Sons of Muspell to monitor the facility where Yuu is staying. They will inform me instantly of any movements. We'll find an opportunity to make contact with Yuu and his gang."

"I am happy to meet the captain... But what exactly is your goal? We still haven't found out anything about Hreidmar's true identity. There's nothing to report to the captain, right?"

Jeanne looked at Kili with wary eyes.

"—I believe that Yuu's group probably came to Japan to take out Yggdrasil. If that's the case, I have something I must tell Yuu... and Tia."

"Tia?"

"Yes, Jeanne-chan. You probably don't know about her, but she's a girl who's together with Yuu's group."

While Kili was explaining, Jeanne caught sight of her face and exclaimed in surprise:

"So you... can make this kind of face too."

"Huh? Was my expression unusual just now?"

Kili widened her eyes and asked. Jeanne nodded and answered.

"It was a very gentle expression. Totally unlike you."

Hearing Jeanne's reply, Kili slowly showed a wry smile.

"—Really? Indeed, that is very unlike me."

Then Kili spoke softly:

"Tia is... the child I raised painstakingly, intending for her to become a real dragon."

Part 2

Twenty-five years ago, Tokyo was devastated by the arrival of Vritra. During reconstruction, rezoning on a large scale was undertaken.

Hence, the city's appearance was quite different from before twenty-five years ago.

Of course, there were some places where the past lingered on, but to me, everything's changed—The driver explained nostalgically.

"Uh... I see."

I concurred vaguely while looking through the window at the scenery outside the vehicle.

I saw rows of towering high-rise buildings, a giant broadcasting tower dwarfing them, as well as a monorail network in three-dimensional interlocking arrangement with the roads. Aeroplanes crossed the sky whose view was narrowed by the buildings obscuring it.

To build up my relationship with Ren, as the first stage in the battle plan, I was going out with everyone, traveling to a nearby amusement park by car.

The driver was a female Asgard member of staff working at the lab. Looking about fifty years of age or so, she was very talkative. In the thirty minutes since we got on the car, she had been talking nonstop the whole time.

She was driving a big van that carried all the students of Brynhildr Class, but Shinomiya-sensei was not among us. As Midgard's representative, Shinomiya-sensei seemed to be busy and had to stay at the research lab.

"Most shocking of all was the destruction of the Tokyo Tower, which disintegrated outright... Because to our generation, it was Tokyo's landmark."

The driver recounted the past with heartfelt emotion, but our feelings could not resonate with things so long ago that were completely unknown to us. Initially, Mitsuki and the others had responded and smiled courteously, but now, they all showed troubled looks.

Tia and Iris did not seem to be listening to her at all. Instead, they were playing around while watching the scenery outside.

Perhaps a bit nervous, Ren simply sat by Ariella with her head lowered silently, not talking.

"I hope things won't get as bad as that again... People who experienced what happened twenty-five years ago are all living in terror. Although the city looks peaceful, the current situation is actually quite grim, you know? Because that super huge tree appeared nearby, bullet trains on the Tokaido are suspended. The only remaining land route to the Kansai region is by detouring to the Hokuriku region. Currently, domestic flights are all overbooked."

The driver kept talking nonstop. Some questions occurred to me at this point, so I asked her proactively for once.

"Will the amusement park still open given what's happening?"

"Oh, you don't need to worry about that. I've already confirmed before we set off. Life sure is tough for amusement park workers. Something of this level isn't enough to give them a day off. But for better or worse, everyone's gotten used to dragon disasters over the past twenty-five years."

The driver smiled wryly and answered as though it did not concern her.

After ten minutes, the van arrived at the amusement park which was open for business as usual, just like she described.

Letting us off at the parking lot where countless cars were parked, she cheerfully saw us off.

"Please have a good time."

"Thank you. There are many places we want to visit on our way back, so we plan on taking public transportation."

"I see, then I'll be heading back now."

Mitsuki thanked her. Nodding slightly in return, she started the van and drove off.

"Phew..."

Watching the car leave, Mitsuki sighed.

"Are we planning to visit other places?"

"...What does it matter? Given this rare chance to visit Japan, we should tour around."

Mitsuki's reply to my question sounded like an excuse.

Perhaps touring around was simply a pretext. She merely did not want to chat with the driver on the return trip.

"This is the amusement park!? It's awesome! Such a huge wheel!"

Seeing the gigantic Ferris wheel visible from outside the park, Tia cried out in excitement.

"Wow! This is my first time to such a huge amusement park!"

Looking at the amusement park's appearance, inspired by fairy tales in theme, Iris felt emotional and excited.

But among the group, Firill showed unease on her face.

"I-It feels like... There are many dangerous looking rides."

I looked towards the park's boundary walls, made to resemble castle walls, only to see a meandering rollercoaster track and a vertical drop attraction. Intimidated by those rides, Firill went pale.

"Eh? Being afraid of thrill rides doesn't fit my image of you, Firill."

Firill's reaction surprised me, so I asked her.

I had almost never seen her act surprised or afraid.

"I'm not afraid of psychological fear, such as horror games or haunted houses... But I can't handle the thrill rides. Unlike flying in the sky by my own power, I feel very insecure about leaving all control to machines..."

"I get it now. Then you don't need to force yourself."

"—No, I have to try my best. I must experience everything at least once, even if it's something I can't handle well. If I'm together with you, Mononobe-kun, perhaps I might even come to love it."

"What...?"

Seeing Firill put on a brave face and smile, I felt quite awkward.

"By the way, Lisa happens to be my opposite. Although she's not afraid of thrill rides, she can't handle psychological fear at all."

"Hold on, Firill-san! Why are you suddenly bringing that up!?"

Hearing Firill, Lisa went red in the face and came near.

"Because I don't want to be the only one to have my weakness exposed."

Knowing Firill was completely unrepentant, Lisa slumped her shoulders helplessly.

"Goodness gracious... Please don't drag me down in your misery. Mononobe Yuu, let me be clear... I am not afraid of haunted houses at all!"

Lisa glared viciously at me and declared solemnly to me.

"G-Got it."

Pressured by her gaze, I nodded and concurred.

This time, Ariella pushed Ren from behind to approach me.

"Okay, Ren, today's goal is to improve your relations with Mononobe-kun, so no more hiding behind my back."

"Mm! Mm—!"

Ren struggled but once she arrived before me, she blushed and bowed her head.

"Sheesh... Ren really is so shy. Mononobe-kun, Ren doesn't hate you, so just guide her gently."

"—Understood."

Seeing Ren so nervous, I felt uncomfortable too, but it would be impossible to get closer to each other like this.

Hence, I stooped down and extended my hand gently to her.

"Don't be so reserved. Anyway, let's have fun together. You really wanted to enjoy the amusement park, right?"

Ren stared at my hand then timidly reached out—and grabbed my sleeve.

"Is that the limit? Hey—don't grab my clothing too."

Ariella smiled wryly and correct Ren who had also grabbed her clothing.

"Mmu..."

However, Ren refused to let go of Ariella.

"—What am I going to do with you? Sorry, Mononobe-kun. Looks like I'll need to accompany Ren until she gets used to you."

"Don't apologize, you're helping me out a lot this way, because I don't have much experience talking to Ren. No wait, about not talking to Ren directly, isn't it the same for everyone?"

I scratched my head but Ariella widened her eyes, cocking her head in puzzlement.

"Huh? I've talked with Ren, you know?"

"R-Really?"

I asked Ariella in surprise. I thought Ren either went "mm" to everyone without exception or typed to communicate on her portable terminal.

"The same goes for me."

"Me too."

Hearing our conversation, Lisa and Mitsuki also raised their hands.

"For me, I guess I can count the occasions on one hand..."

"Actually, it's only a few times for me."

"Only twice for Tia!"

Although not many times, Firill, Iris and Tia still had experience talking with Ren.

"Mononobe-kun, Ren does know how to talk, it's just that... She's a bit timid. Once you build up your relationship with her, I'm sure you'll be able to talk with her."

Ariella stroked Ren's red hair while talking to me.

"Oh okay, I get it now. So talking with Ren will be my first goal."

I finally understood what Lisa meant by the issue before practicing.

Namely, I probably had not even reached the starting line.

I could feel Ren's faint tugging on my sleeve. Since Ren was working hard for us to get closer, I must do my best too.

"Everyone, let us head to the entrance."

"Yes."

Responding to Mitsuki's call to all of us, I walked side by side with Ren and Ariella.

Part 3

Lively background music was playing inside the park. Visitors were surprisingly few.

Only then did I remember that today was a weekday. Rather than families on an outing, most visitors were couples or what seemed to be students on school trips.

Dressed in uniform, we were probably seen as students on a school trip too.

A penguin, probably a park mascot, was handing out balloons to children. However, due to that penguin's oppressive stare, abnormally slender appearance and sinister airs, the children fled as soon as they took their balloons.

That kind of design was probably going for the creepy-cute effect. Although disliked by children, it had a crowd of middle school girls as fans, competing to take photos with it.

"Oh Mononobe! That penguin is so cute!"

Iris' sensibilities also seemed to recognize that thing as cute. With an excited look on her face, she pointed at the penguin mascot.

"Y-Yeah."

I did not really want to approach it but could not bring myself to act as a killjoy, so I agreed in a stammer.

"Eh... Tia finds it scary."

However, Tia frowned and voiced her opinion.

"Mm."

Clutching my sleeve, Ren nodded in agreement. As expected, it was not quite accepted by the lower age bracket.

"Then let us try that ride first? I am very curious about that attraction where screams have been coming continuously for a while now."

Lisa pointed at the roller coaster excitedly. Just as Firill mentioned, she seemed to prefer thrill rides.

"I haven't prepared myself yet... I want to ride something more stable."

Firill objected with a stiff expression.

"Ren is nervous too, so let's go with that. Also, we should start with something that everyone can ride together as much as possible."

Ariella suggested.

"Then how about we begin with that?"

After listening to everyone's opinion, Mitsuki pointed at the most fairy tale-like of attractions in this amusement park removed from daily life—A merry-go-round.

I felt reluctant to ride a merry-go-round at my age, but I did not voice my objections.

Because Ren was tugging my clothing hard with excitement on her face.

"—Then let's go for a ride."

I answered Mitsuki and Ren nodded in joy.

Thus, we headed to the first attraction.

"Wow, this is great! It keeps spinning round and round!"

Riding on a white horse, going up and down as the merry-go-round spun, Tia said happily.

"This brings back memories."

"Indeed, it reminds me of childhood."

Mitsuki agreed with Iris. Having lost my memories, I could not remember, but I had probably gone to amusement parks with Mitsuki and our family many times in the past.

It really did feel sad to lose what were supposed to be shared memories.

"I'm dizzy..."

Firill seemed unwell already. Riding together, she was leaning against Lisa.

Ren, Ariella and I were sitting in carriage-style space, looking at the park scenery spinning around us.

Ren leaned out of the window to wave at everyone. It was hard to associate her excited appearance with her usual behavior.

"Ren, you seem quite happy."

"Mm."

I asked Ren and she immediately nodded in agreement.

"It seems you wanted to visit an amusement park in the first place. Is there a reason?"

However, when I continued to ask more, she fell silent with a hesitant look on her face.

Had I asked something I shouldn't? I looked at Ariella.

"...I don't know Ren's reason for wanting to visit an amusement park either. If there's any reason, it might date back to before I became family with Ren."

Ren nodded at what Ariella said.

"...Mm."

"I see. Since it's difficult to talk about, no need to force yourself. I'm just curious, that's all."

It was rare enough for Ren to enjoy an amusement park. Not wanting to ruin her fun, I decided not to pry.

"Mm."

Ren smiled, somewhat relieved, then turned her gaze outside of the carriage again.

Although I felt a bit impatient to get to know Ren as quickly as possible, questioning forcibly did not seem to be the way.

—I should first tell her about myself.

Of course, one would not carelessly talk about themselves to someone they did not trust. I must get Ren to know me first.

I switched my mode of thinking and motivated myself.

If there was any problem, it was probably that the self I ought to present honestly was already lost for the most part.

Would Ren be willing to believe in such an ambiguous me...? I definitely had no confidence regarding this point.

After the merry-go-round, we rode the coffee cup and finally challenged the roller coaster.

With seats in pairs, this roller coaster was the most traditional type, but the track was apparently the longest in the entire country. Winding and meandering, the circular course definitely covered the entire premises of the amusement park.

"Kyah!"

"So fast!"

Despite fearing the rapidly descending roller coaster, Iris and Tia still enjoyed themselves.

"This is rather fun."

"Since I normally fly faster than this, it is not thrilling enough."

Lisa enjoyed the thrill of the roller coaster with a collected expression, while Mitsuki offered her opinion calmly.

"Let me down—!!"

Among these girls, Firill was the only one screaming her heart out.

"...!!"

Sitting next to me, Ren had her eyes tightly closed, gripping the safety restraints desperately.

"Ren, you won't fall off, so open your eyes and look. The scenery is great."

When going on an uphill stretch and the speed was slowing down, I spoke to her.

"Mm......!?"

Ren opened her eyes slightly but as soon as she saw that we were entering a rapid descent again soon, she hastily closed them again.

"Mononobe-kun, you don't seem fazed at all."

Sitting behind us, Ariella spoke to me.

"Ariella, the same goes for you."

Due to the restraints, I could not look back, but there was no tension in Ariella's voice.

"Well, that's because I'm already used to scary things."

I could sense heaviness in the meaning behind Ariella's reply, causing me to frown.

"Ariella, that's—"

"We're about to make a rapid descent. You'll bite your tongue if you speak, you know?"

Mid-sentence, Ariella cut me off so I stopped talking.

Then the roller coaster descended, bringing acceleration that seemed to make our stomachs rise, as well as the ground rushing towards us fiercely in view.

"Kyah!"

Ariella yelled happily behind me to go with the flow of everyone's screaming.

"I can't take anymore of this!"

I heard Firill's crying too.

Ren kept her eyes shut to the very end, enduring the blowing wind—

After the roller coaster, we headed to a haunted house that was made to resemble a creepy western mansion.

Lisa looked like she wanted to try other thrill rides, but Firill and Ren seemed quite exhausted so we decided to have a break from those.

This time, it was Lisa and Tia's turn to lose composure.

"...Why are you all gathering by my side?"

Advancing along the creepy corridor that was lit by pale lighting, I asked the girls surrounding me.

"I-I simply fear that you would get lost because it's too dark."

Clutching my shoulder, Lisa answered in a trembling voice.

"Yuu... Tia is so scared."

Hugging my waist, Tia walked with her eyes closed.

"Nii-san, you must protect us like a man in times like these."

Mitsuki answered calmly while holding onto my clothing from behind.

"What are you asking me to protect you from...?"

It was not as if the monsters would attack us directly. I could not help but sigh.

Ren was expressionless so far, but she was gripping my sleeve quite forcefully. She seemed quite nervous inside.

"What will show up...?"

"This atmosphere suggests something like Dracula, right?"

Firill and Ariella were chatting in delight.

At this moment, dark silhouettes of monsters appeared at the window along with rumbling sound effects of thunder.

"Kyahhhhhhh!!"

Iris hugged me from behind with Mitsuki in between.

"What... Wait, Iris-san!"

"Uwah!?"

Someone wrapped their arms around my neck, choking me.

"Eeek!?"

Lisa emitted a brief shriek and leaned against me.

Tia hugged me tightly. My entire body was rendered immobile.

The soft parts of girls were in contact with various spots on my body, forcing my heart rate to accelerate.

Ren was hugging my arm from fright but immediately realized in alarm and released me.

Seeing this, Firill's face seemed to be saying: Crap.

"Oh no... They got ahead of me. I've been looking for a chance the whole time."

"Well, I don't think they're doing this on purpose, are they?"

Firill remarked regretfully while Ariella retorted calmly.

"Fine, here I go!"

"Hey..."

I was already stooping from all the girls clinging to me. Firill pounced from the front and hugged my head against her chest.

With my face buried in the soft and voluptuous bosom, a fragrant scent caressed my nasal cavity.

"Firill-san! What are you doing, taking advantage of the situation!?"

Mitsuki frantically scolded her.

"But Mitsuki, aren't you sticking together with Mononobe-kun?"

"T-This is because I am being squeezed from behind—Iris-san, could you please back away?"

Faced with Firill's rebuttal, Mitsuki advised Iris.

"No way! I'm so scared. I'll keep my eyes closed so please lead me to the exit like this!"

However, Iris kept Mitsuki sandwiched between me and her, refusing to move away.

"Mononobe Yuu, hurry and move forward! Because you stopped, we cannot leave."

Holding onto my shoulder, Lisa commanded.

"Yuu! Husband must protect wife!"

Hugging my waist, Tia yelled loudly. Ren kept tugging at my sleeve.

"No way? You're asking me to move forward in this posture...?"

I replied in disbelief. At this time, Ariella laughed at my misfortune, far away from us.

"Do your best, Mononobe-kun. This is the time to show your mettle as a man."

"......Sigh, got it."

I gave up resisting and sighed, then poured strength into my entire body.

Dragging all the girls clinging to my body, I finally reached the exit, exhausted and drenched in sweat.

"I'm dead tired..."

Having used up plenty of stamina at the haunted house, I sat on a bench and looked up at the sky.

Split by the roller coaster track, the blue sky showed white clouds moving slowly.

Right now, we were at a food court in the amusement park.

The sun had climbed up to the very middle of the sky. Since everyone looked like they needed a break, we decided to have lunch here.

I was sitting next to a large table on the edge of the food court, saving seats. Leaning my weight against the backrest, I focused on recovering my energy.

The others had gone to the shops surrounding the food court to buy food. Since I had asked them to buy my share, all I had to do now was wait.

"Mononobe-kun."

While I was spacing out at the sky, Ariella's face suddenly appeared in my view.

"Oh... You're already back? I can't believe you suppressed the sound of your footsteps to approach me. That's a nasty hobby you've got."

Feeling shaken, I grumbled at her. Even though I was in a relaxed state, I could not believe I had failed to notice her approaching at all.

"Fufu, because I wanted to scare you. The others are arguing about what to buy you for lunch, so I decided to come back alone first."

Ariella smiled mischievously then sat down beside me. She was holding a hotdog.

I swept my gaze throughout the food court and saw Mitsuki and the girls definitely in a dispute over something.

"I was definitely startled. You're no ordinary person, Ariella, whether the way you conceal your presence or the martial arts I saw last time. And you said you're Director Miyazawa's adopted daughter... Can you explain a bit of this to me?"

I asked nervously.

Since yesterday, I had been very curious, but because it was not the right moment, I gave up asking at the time. But given the current mood, I felt she probably would answer.

"—Very well. I guess I'd better tell you to help improve your relations with Ren, Mononobe-kun."

Ariella took a bite of the hotdog then nodded and began to recount the past.

"I mentioned before... I was born in a country where conflict was constant. My loved ones got caught up in human conflict and lost their lives. The yellow dragon—'Yellow' Hraesvelgr—ate their souls. Back then, I hated Hraesvelgr extremely so I joined a certain organization."

"A certain organization?"

Hearing this vaguely worrying term, I frowned.

"An organization embracing an ideology opposite to dragon worshiping cults like the Sons of Muspell, in other words, a dragon hating organization. They were quite a radical organization. That was where I learned combat arts."

"What... But I remember that those types of organizations hated Ds too, right?"

While feeling surprised and puzzled, I asked Ariella.

"Yes... That's why I could only stay in that organization until my dark matter powers awakened. Having become a D, I was that close to being killed, but due to the organization's mercy, I was sold to Miyazawa Kenya through black market trading."

"W-Wait, isn't that human trafficking!?"

Ariella spoke lightly but selling Ds was undoubtedly a crime.

"That's right. At the time, he was exiled from academia due to his Ether Wind paper. To conduct private research, he intended to obtain Ds as research samples through illegal means. I've heard that he amassed a large fortune through many patents but almost spent it all."

Ariella shrugged and spoke in a tone of resignation.

"Then the title of adopted daughter is..."

"Merely for appearances to the outside world. However, he did treat me with courtesy and never did anything I hated. Initially, I thought he was a good person, but after he introduced Ren to me as my 'little sister' and I saw his attitude towards her, I realized I was wrong."

Ariella's voice conveyed slight anger. She continued:

"The reason why he took care of me thoughtfully was because his research needed me... He was cold to Ren who was unrelated to research. The more I got closer to Ren, the more anger I felt towards him... I did not lack freedom in my life and I was quite contented about that, but—"

Then Ariella's expression turned gloomy.

After checking that Mitsuki and the others were not returning yet, I urged her to continue.

"But what?"

"...Ren's dark matter generating ability also awakened. After finding out, this was what he said: 'Now that there are two samples, I guess it's fine to up the intensity in the experiments.'"

"What...? He intended to use you or Ren until one of you broke?"

Hearing what Ariella said, I gasped. Anger gradually surged in my heart.

"Probably. That's why I took Ren and ran away, seeking police protection. As a result, he was arrested for human trafficking and concealing Ds, whereas we were sent to Midgard. However... In the end, he was not punished by the law and went on to climb to his current position."

"Why...?"

Unable to accept it, I asked. Ariella replied without disguising her discontent at all:

"Probably because his research has value to Asgard. Maybe some sort of plea bargain using the content of his research. I don't know the details but he's someone who belongs in jail, that's for sure."

Ariella spat on him with a look of disdain.

"You hate him, Ariella?"

"He didn't do anything to me. If he hadn't taken me in from that organization, I might have been killed, so I shouldn't hate him. It's just that I'm furious about Ren. It's all his fault that Ren almost never speaks."

Ariella turned her gaze to Ren who was together with Mitsuki and the girls, then said clearly.

"What happened there?"

"Ren's mother passed away a long time ago, far earlier than when I was adopted. After that, he buried himself in research. Even when Ren tried to talk to him, he'd only go 'shut up' and ignore her. I think because those kinds of days lasted for too long that Ren gave up speaking."

"Gave up speaking..."

That was extremely sad. Heartrending words.

"But Ren actually wants to speak, because she's clearly talkative when she types."

"—Yeah."

I smiled wryly and agreed.

Ren's typed speech was always so overbearing, it even made me feel that she was very foul-mouthed. But this meant that her mind was filled with words she wanted to speak.

"Ren is scared of being scolded 'shut up,' so as long as you make her feel reassured, Mononobe-kun, it'll be fine once she knows you won't say anything like that. Don't worry, I'm sure you'll succeed."

Ariella smiled cheerfully and asserted.

"I'm happy to hear that from you... But it makes me uncomfortable all over. I thought you'd say harsher things to me, Ariella."

I scratched my head in embarrassment.

"We've lived together and fought side by side till now. This is my revised view of you after many observations. Although I said a lot of harsh things when you first came to Midgard, I trust you now."

Ariella looked away in embarrassment too and took another bite of her hotdog.

The conversation halted. We were plunged into an uncomfortable silence.

"Oh right, Mononobe-kun, wanna have a bite?"

As though trying to dispel that atmosphere, Ariella presented her half-eaten hotdog to me.

"Huh, I can?"

"Yeah, the others are taking so long, you must be hungry."

Without turning her head back after looking away, Ariella extended the hotdog closer.

"Okay... Thanks for the food."

I accepted Ariella's kind offer and took only one bite of the hotdog.

The hotdog's sweetness from fat and ketchup, spiciness from the mustard, and the soft texture of bread expanded in my mouth.

"Mmm, it's good."

"Glad you like it."

Ariella smiled after hearing my comment.

"But I thought you wouldn't want to do this, Ariella."

"...Why?"

Eating the hotdog I had bitten, Ariella tilted her head in puzzlement.

"Uh, because this is an indirect kiss, right?"

The instant I said that, Ariella's entire person froze. Instantly, she went red in embarrassment.

"I-I didn't mean to—"

Seeing her reaction, I realized she simply had not realized.

Although Ariella was greatly flustered, since the hotdog was already in her mouth, she had no choice but to chew and swallow the mouthful with a reddened face before glaring coldly at me.

"...So you ate in despite clearly knowing that, Mononobe-kun?"

"Well... Because you didn't seem to mind, I thought I'd better not mind either."

I answered awkwardly.

"I-In that case, then keep it to yourself to the very end."

Licking off the ketchup on her fingers, Ariella muttered with her face red.

Part 4

After lunch, everyone started enjoying the attractions again. Time went by in an instant when having fun.

By the time I realized, the sun was already setting in the west. The sky was starting to be dyed orange-red.

"Best not to return too late, so this will be the last ride."

Looking up at the mechanical clock in the park, Mitsuki suggested.

"If that's the case, I guess we have to ride that at the end."

Ariella pointed at the attraction whose presence surpassed even the roller coaster—The giant Ferris wheel.

Gripping my sleeve tightly, Ren nodded with excitement on her face. She looked like she had been looking forward to it for a long time.

Thus we made our way to the Ferris wheel. When we arrived right under it, I discovered that it was so huge that looking up at it hurt my neck.

Since a single car could not contain all of us, we split up into groups of four.

"Then I shall go with Mononobe Yuu, Ren-san and Ariella-san first."

Lisa suggested. Strangely enough, the remaining Mitsuki, Iris, Firill and Tia agreed obediently.

"Yes, take care!"

I felt especially strange to see Tia, who was potentially the most clingy, waving her hand without making a fuss.

When it was our turn to board the Ferris wheel, I finally understood the truth of that dissonance.

Originally supposed to follow us, Ariella and Lisa waved from outside the car.

"Eh? Why aren't you two coming?"

I asked in surprise but Ariella immediately smiled mischievously.

"You two should have fun alone at least in the end. It's about time that Ren no longer needs me by her side, right?"

"Mm! Mm!"

Ren shook her head anxiously but the park staff closed the door and the car left the ground.

Without saying a word, Lisa's face seemed to convey "do your best" while she saw us off.

"...We got tricked. They must have agreed on this beforehand."

With the two of us alone in the car, I smiled wryly at Ren who was sitting opposite me.

"Mm..."

Ren nodded with a slightly angry demeanor. As soon as she met my gaze, she hastily looked down.

The bright rays of the setting sun entered the rising Ferris wheel car.

"Are you still nervous?"

Squinting from the setting sun's brightness, I asked her. She nodded slightly in response.

"To be honest, me too."

Hearing me say that, Ren looked up slightly to show a surprised expression.

"Because I've never had the experience of riding a Ferris wheel alone with a girl. Suddenly thrust into this date-like situation, I can't stay calm after all."

"...!"

Ren went red and stiffened, apparently even more nervous.

"Oh, sorry, I made you even more nervous. But I'm very grateful to Ariella who made this opportunity for me. Given this rare chance, while the Ferris wheel completes a revolution, will you listen to me?"

I cautioned myself to be as gentle in tone as possible then asked Ren.

"......Mm."

After a brief silence, Ren nodded.

"Thank you. I think I need to say something first... I asked Ariella to tell me many things about the past, including about you, Ren."

Ariella's experiences as Miyazawa Kenya's adopted daughter, the passing of Ren's mother, the reason why Ren no longer spoke—I knew many things one-sidedly.

I thought that it would be unfair after all.

"So this time, I'll tell you about myself. Right now, I'll tell you everything I can think of."

"...?"

Ren showed puzzlement at the way I spoke.

"Actually, I have a secret. Apart from these three—Iris, Lisa and Principal Charlotte—I've never told anyone."

Despite feeling hesitant, I still continued.

"I don't want Mitsuki to know of this no matter what... That's why I haven't told anyone else. But Ren, I'm trying to help you understand the 'current me' because I believe I need to come clean to you about everything. If I continue to hide myself, I don't think I can gain your trust no matter how much time I spend."

I gazed at Ren with a solemn expression. Perhaps feeling my determination, Ren sat up straight and looked into my eyes.

"Mm."

"Tell me"—Ren seemed to be urging me.

Then I began to recount. How I contracted with Yggdrasil three years ago to obtain pre-civilization weapons data in exchange for memories; how I was caught by NIFL after that and fought as part of the special forces team Sleipnir, how my commanding officer, Major Loki, intended to raise me as the strongest killer named "Fafnir"—

Ren focused her gaze on me while I talked nonstop.

"—Then because Mitsuki applied pressure on the higher-ups, I was reassigned to Midgard and everything after that happened as you know, Ren... The anti-dragon armaments I used during the battles against Leviathan and Hraesvelgr were downloaded from Yggdrasil using more of my memories as the price. The result is that I've lost virtually all my memories beyond three years ago."

"......"

Ren inhaled slightly, widening her eyes.

"And within the data downloaded from Yggdrasil, there's something like a computer virus. Controlled by Yggdrasil... I almost took Lisa's life. It's also my fault that Yggdrasil suddenly appeared at the school festival. You were in danger at the time too... I am truly sorry."

I bowed my head deeply to apologize to Ren. Actually not just Ren, I needed to apologize to Ariella and the other girls as well as Lisa's parents who were caught up in the incident.

However, if the outside world were to find out it was my fault, the position of Midgard and the Ds would be at risk. Since the principal covered up what happened with me, it must not be disclosed lightly.

"Currently, the principal has done a lot for me to prevent Yggdrasil from controlling me, but it's unknown how long it'd last. It's because of me that we are rushing to take down Yggdrasil. I'm very sorry for getting you and everyone else involved because of that."

The more I said, the more I became aware of how much I had deceived and kept things from others. I could not help but fall into emotions of self-loathing.

Mitsuki's face flashed in my mind. More than anyone, I had deceived her.

—I was truly a liar.

Despite owning up to everything, I did not think that Ren would trust someone like me. To be honest, even though I had revealed everything, my crimes would not disappear.

Unsure how to face Ren, I kept my head down. Then I felt an impact on the back of my head with a knock.

"...Ren?"

I looked up to see Ren glaring at me with her hand in a fist.

"Mm!"

Ren made a scolding sound and took out her portable terminal, typing swiftly then showing me:

"—You should've said so earlier. Now isn't the time to be having fun in this kind of place. Hurry and go back to practice dark matter transfer..."

I read out the words displayed. Ren kept nodding.

"You're not angry?"

I asked in surprise. Ren typed again.

—I'm angry but now isn't the time for anger.

As I read the words on the screen, my shoulders instantly relaxed.

"Thank you, Ren. You're so kind."

"...!"

I thanked her. Ren went red and looked away.

"I'd like to hurry and master dark matter transfer too, but I think just as Lisa said, right now what we need is communication. So I'd be grateful if we could talk here some more."

Our car was about to reach the highest point of the Ferris wheel, so there was still time to talk.

"...Mm."

Ren took a deep breath, trying to calm herself. While thinking, she typed on her terminal.

—I know. Ask anything you want. I will answer everything honestly.

With a serious expression, Ren raised her terminal in front of me and made this suggestion.

"So, can you tell me why you wanted to come to an amusement park?"

She refused the first time I asked, so it was probably something difficult to talk about.

But I could feel that it might be the first step to understanding Ren if this was the reason that even Ariella did not know.

Ren's expression instantly froze. Then she nodded and began typing on the terminal.

The following words were displayed on the screen facing me—

—Because I visited an amusement park with Father and Mother before and had a great time.

"So that's why..."

Normally speaking, that would not be a difficult reason to bring up, but Ren's mother had passed away and Miyazawa Kenya had now buried himself in research, neglecting Ren coldly.

If she told others the reason, she would have to confront the gap between past and present. That would make Ren suffer, which was why she refused to answer.

"What kind of person was your mother like?"

—Cheerful and bold, she often led my wimpy father around by the nose.

Reading what she typed, I could only smile wryly.

"She must be quite a spirited woman."

Hearing my comment, Ren nodded in agreement and typed her answer.

—Yes, she's a bit similar to Onee-chan.

"Onee-chan?"

I asked in puzzlement and Ren hastily typed again.

—I mean Ariella.

"Oh, I see. So you usually call Ariella Onee-chan."

"...!"

Ren immediately blushed and silently hammered my kneecap.

"No, there's nothing to be shy about. It means you think of Ariella as your real family, right?"

Hearing me ask that, Ren nodded slightly with a blush.

—Right, so Ariella is the only one I can talk to normally.

Reading the words on Ren's raised terminal, I smiled.

"I'm so jealous. If only I could be that close with you."

"......"

Hearing me say that, Ren showed a look as though she suddenly understood something. She stared at me silently.

"What's up?"

Feeling intrigued, I inquired but Ren looked down at the terminal on her hand.

Then after a minute, she slowly typed in text.

She probably had some kind of message for me, so I waited quietly for her to finish typing.

"......Mm."

Then shown on the terminal's screen was a very brief sentence that had taken her a long time to type.

—Can I call you Onii-chan?

"Huh...?"

I looked at Ren's face in surprise. Blushing to her ears, she lowered her head.

"Mm!"

But Ren did not put down her terminal. She urged me to answer.

Perhaps this was Ren trying her hardest. In that case, I had no reason to refuse.

"—Yeah, you can."

Hearing my answer, Ren hugged the terminal to her chest and looked at me with her face red.

"......"

Opening her mouth, Ren looked like she wanted to say something but could not.

Perhaps...

Seeing her like that, I noticed.

Ren had asked me "can I call you Onii-chan?" which meant that—

"...O......"

Ren's breath carried a faint voice.

"O... Oni......"

Her trembling voice was gradually weaving words.

".......Oni... Onii..."

As though exhausting her strength, the tiny voice was gradually connecting together.

Feeling her struggle and nervousness, my heart also began to beat faster and faster.

Inside the Ferris wheel car touring the sky, the atmosphere was so tense that it pricked my skin—

"...Onii, -chan."

I hear a voice so delicate it was almost covered up by the sound of wind.

In that instant, indescribable joy and embarrassment filled my heart.

"Y-Yeah."

Infected with her nervousness, I answered hoarsely.

Immediately, Ren's entire body relaxed with a look of relief on her face.

"—Onii-chan."

Then in a more natural tone of voice than before, Ren repeated the same words.

"Yeah."

I answered again, slightly recovering in composure.

Ren happily relaxed her facial expression and showed a gentle smile.

"Onii-chan."

"Yeah, I'm your older brother from now on, Ren."

"Mm."

Ren nodded, swaying her legs happily.

After that, Ren kept calling me "Onii-chan" and I answered every time in embarrassment.

"Onii-chan" were the only words Ren spoke so our interaction could not be called a conversation, but the more we repeated the exchange, the more I felt that we were growing closer.

Just as we were doing this kind of thing, the Ferris wheel finished a revolution and returned us to the ground.

"Ren."

I got off the car first and reached out to Ren.

"Mm."

Despite some hesitation, Ren held my hand instead of grabbing my sleeve this time.

Then using my hand for support, she got off the car and said with blushing cheeks:

"Onii-chan...... Thank you."

Part 5

"Of course I'm happy that the plan went smoothly... But what on earth did you do to Ren-san? I feel that you have grown a bit too close."

After we got off the Ferris wheel and went to meet everyone, along the way to the park exit, Lisa looked at us in surprise.

Ren was gripping my right hand tightly, smiling with delight on her face.

The sun was about to disappear in the west. The western sky was red. Looking east, I could see the first star shining in the night sky.

"I'm curious too. Can I ask the reason, Ren?"

Looking quite curious, Ariella asked Ren.

Feeling gazes from Mitsuki, Iris, Firill, Tia and everyone else, Ren lowered her head shyly.

"......Onii-chan."

Ren called to me quietly and pulled my hand.

Hearing her say that, the girls broke into a commotion.

"Ah, I get it now. You often said you wanted an older brother, Ren, so your dream has come true now, right?"

Ariella seemed to understand completely from hearing one sentence from Ren. Smiling, she rubbed Ren's head.

"...Mm."

Ren looked down and nodded mildly in confirmation.

"W-Wait, so that means Nii-san is willing to become Ren-san's 'Onii-chan'?"

Greatly shaken, Mitsuki asked immediately.

"Well, something like that."

I answered with embarrassed feelings. Mitsuki instantly looked offended.

"What do you mean, something like that...? Let me tell you, Nii-san, brother-sister relationships do not come about so lightly—"

"Eh? Don't tell me you're jealous, Mitsuki?"

Mid-sentence, Firill interrupted.

"What... I-I am most certainly not jealous!"

"Really? Then what's the problem? Even though she's calling him Onii-chan, it's just an intimate way of addressing someone slightly older."

"I know that, but..."

Mitsuki reluctantly stopped complaining but still looked at me with eyes of unease.

I had no blood relation to Mitsuki. As siblings in name only, she could not remain complacent. Perhaps she felt anxious as though her position was being stolen.

"Don't worry, Mitsuki, I won't stop being your brother."

"Ah... S-Sure."

I comforted her but the gloom on Mitsuki's face did not dissipate completely despite her smile.

Did I word it wrong? Sure enough, with my lost memories, I was unable to guess Mitsuki's feelings.

"Tia won't be jealous! Because Tia wants Yuu to be Tia's husband, not big brother, but... Tia wants to hold hands too."

Tia stared at my hand that Ren was holding. Because my left arm was in a cast, I could not hold hands with two people at the same time.

"Tia-chan, don't disturb them right now. It's not easy for Mononobe and Ren-chan to become closer."

Iris advised Tia with a wry smile.

"That's true, but... Aren't you jealous, Iris?"

"Eh? I-I'm also..."

Momentarily at a loss for words, Iris looked at me with a complicated expression. Her reaction made my heart rate accelerate.

"See, Iris is like Tia, so according to the order—"

Tia made an "I knew it" look and was just about to make some sort of suggestion when she stopped mid-sentence.

"Eh?"

It really happened in an instant.

A figure dashed over, picked up Tia from behind and ran away just like that.

Since it was too suddenly, no one could instantly grasp what had happened, including me. Even so, I was still the first to come to my senses. Letting go of Ren's hand, I instantly gave chase.

"Hold it right there!!"

What the heck—Who on earth...?

Despite the questions filling my mind, I did not have the luxury to ponder. In any case, I had to rescue Tia.

"L-Let Tia go!"

Skillfully carrying the struggling Tia while escaping was a slender young man. His blond ponytail fluttered behind him in the wind.

Could... that be John?

Seeing a familiar looking back, I realized the perpetrator's identity.

"John!"

As soon as I called his name, he instantly looked back. It really was John.

However, John did not slow down. Thus he ran into one of the nearby buildings.

This was an attraction named the "Castle of Mirrors." As suggested by its name, the castle's interior design consisted of mirrors covering the whole place. Entry seemed to be unrestricted with no staff at the entrance.

It was already close to nightfall. Since people were gathered at attractions designed for admiring the scenery, the Castle of Mirrors was empty without anyone in sight.

"Nii-san!"

"Mononobe! Where's Tia-chan!?"

I stopped. Mitsuki, Iris and the others caught up.

"—Inside here. It's John who abducted Tia, which means that Kili might be here too, because yesterday, she mentioned about talking next time... I think she probably wants to talk to me here."

"Doing things coercively as usual... If she wants to talk, why can't she do it openly?"

Lisa commented in frustration.

"Mononobe-kun, we'd better chase quickly."

Although Firill urged me, I shook my head after thinking briefly.

"No, Firill, you and the others should guard the entrance and the surroundings. I'll go inside by myself. In case a fight against Kili breaks out, I'm the only one who can oppose her."

Saying that, I broke into a run without waiting for their response.

"Onii-chan—"

"Hold on, Mononobe-kun!"

I heard Ren and Ariella's voices behind me but did not look back.

Entering the Castle of Mirrors through the entrance that was styled like a gate, I suddenly found myself about to collide with my mirror image.

"...!"

I reflexively guarded myself then exhaled.

The interior was just as expected, a corridor covered with mirrors. Oppositely facing mirrors produced countless virtual images.

As a result, it was impossible to judge the length and width of this corridor accurately. Running recklessly would probably collide into a wall.

Left without a choice, I could only advance by walking briskly.

"Tia! Where are you? John! Answer me!"

I called out but did not get any response.

But after turning for who knew how many times, I saw John.

In the passage there, even the floor and ceiling was covered with mirrors in addition to the walls.

In that space where the feeling of up and down would become unstable, John was standing there quietly.

"—Thank goodness, I'm so glad that you came alone, Captain. If others came along, I'd have to stall you all here."

"John... Why are you doing this? Where's Tia?"

I slowed my pace and entered a combat stance while asking him. I could not see Tia anywhere within my field of vision.

"She is talking inside with Kili."

"Then I'm going over."

I planned to advance but John raised a hand to stop me.

"Sorry, please wait a while longer. Kili seems to have something important to tell her."

"...John, when did you become Kili's underling?"

I glared at John without hiding my irritation.

"I told you yesterday, I didn't become Kili's friend. I'm only joining forces with her due to certain reasons."

"Reasons?"

I asked her with my gaze.

"Well... I can't tell you. While key facts remain unknown... Even if I told you incomplete information, it would do nothing but cause you trouble, Captain."

Seeing John's apologetic look when replying to me, I exhaled.

"I understand you have your reasons for doing this, but I can't accept it unless you explain to me. Sorry, I'm heading over because I'm worried about Tia."

I took a step forward and John instantly turned to enter a stance.

"—My apologies, Captain, then I'll have to delay you for a while."

"If you want to fight, I won't show any mercy."

Anti-personnel weapon—AT Nergal.

I generated dark matter in my right hand, transmuting into a projectile-based electroshock gun. My palm instantly felt the gun's familiar weight.

"Be my guest. Your left arm seems unusable right now, so I have a chance in this environment."

As soon as he said that, John instantly kicked the ground and closed in on his own initiative.

I was momentarily confused by this unexpected move. John was a sniper. Although he had gone through martial arts training, it was much cruder compared to what other Sleipnir members and I went through. In addition, John was not carrying any weapons right now.

Starting a close quarters fight against me while unarmed would be a foolish act of overconfidence.

While approaching me, John swung an acute punch at me.

With minimum motion, I dodged while moving forward, executing a sweeping kick the instant I passed by him.

However, I did not feel the kick connect.

—Hmm?

Jumping to dodge my sweep, John turned in the air to perform a spinning kick.

Unable to use my left arm, I could not block this attack coming from the left. Without a choice, I could only duck to evade. John's leg brushed past the back of my head.

Maintaining this posture, I aimed Nergal's muzzle at John.

His movements were more nimble than I predicted. Although I was a little surprised, this was the end. Since he was in midair, there was no way he could dodge my attack.

But just as I was about to pull the trigger, my instincts sounded the alarm.

John's extended arm was aimed at me. A metallic glint could be seen inside his clenched fist—

"!?"

I made a split-second decision and swung Nergal.

Clang—a hard sound rang out and I felt a strong impact transmitted through Nergal.

A coin flew up in the air, spinning as it fell.

"Flicked huh—"

Most likely, he was holding the coin in his hand from the start, then he flicked the coin fiercely with his finger.

Although no match for handguns, the firepower of flicked projectiles at close range must not be underestimated. A single clean hit on the center of the forehead could result in unconsciousness.

Seizing the chance when I switched to defense, John instantly launched flicked projectiles consecutively with both hands as soon as he landed.

However, flicked projectiles were a type of ambush technique. There was nothing to fear once they were known in advance.

Precipitating my ego, I slightly awakened the "Fafnir" dormant in the bottom of my subconscious.

My sharpened senses captured John's killing intent and transmitted the trajectories of his flicked projectiles to me. Evading all projectiles simply through dodging, I aimed my gun at John.

"It's over."

I pulled the trigger. A single hit from this projectile-based electroshock gun would instantly render the target unconscious.

However, John evaded my attack as though he had predicted my bullet trajectory.

"What..."

Seeing me surprised, John showed a happy smile on the corner of his lips.

"Indeed, that shot would have ended things if I were still the one you knew."

"I can't believe you dodged that... You've become stronger."

I praised him and John scratched his face uncomfortably.

"No... It's not because I got stronger, but thanks to this location."

He pointed at the corridor covered with mirrors and continued:

"I was scouted for my eyes that are superior to others, thus becoming a member of Sleipnir. In this space filled with mirrors, Captain, I can observe your movements from all directions. Simply through vision, I can gather several times more information than usual, which improves the accuracy of predictions."

"So that's why my attacks all missed."

Hearing John's explanation, I sighed.

"Even you will take a fair amount of effort to defeat me currently. But if you intend to kill me—Things might be different."

John gazed at my eyes in a probing manner and spoke.

"......"

I faced off against John, thinking what to do. But before I reached that conclusion, I heard a cellphone ringtone in the surroundings.

"—This is a call from Kili. Looks like there's no need to stall longer."

John took out his cellphone from a pocket and spoke with relief.

I breathed a sigh of relief too.

"Then can I go over?"

"Yes. But rather, I will lead the way because it's a maze inside."

John released his combat stance completely and walked deeper into the corridor.

The originally tense atmosphere eased up. I placed Nergal into an inside pocket of my uniform.

In the end, I had simply increased my fatigue for nothing. I sighed while following John.

The castle's mirror-filled interior was truly full of complicated intersecting paths. Even if I had defeated John, it would have been impossible to find Tia quickly. Kili must have chosen the Castle of Mirrors with this in consideration.

Tia and Kili were in a great hall that seemed to be in the center of the maze.

"Ah—Yuu!"

Seeing me, Tia ran over in joy.

Tia pounced at my chest. I caught her and looked at Kili standing in the center of the hall.

"Kili... What is your goal in doing this?"

"Because I needed to talk to Tia in private without being disturbed by anyone, that's why I invited her to this Castle of Mirrors. This happens to be a great place to help her scrutinize her own existence anew."

Kili answered nonchalantly without any conscience at all.

I gently asked Tia, who was clinging to my waist.

"Tia, did she do anything to you?"

"...Don't worry, we were just talking."

Tia looked up and answered. However, her voice lacked vitality. I felt concerned by Kili's mention of "existence."

"What did you talk about?"

"Umm..."

Tia stammered in response to my question. I looked at Kili again to seek an explanation.

"—Unfortunately, the explanation cannot come from my lips. Including whether to tell you or not, everything will be decided by Tia on her own, so I will talk to you about something else."

Kili narrowed her eyes and responded in monotone.

"Something else?"

"That's right. Since your group has come to Japan to defeat Yggdrasil, there's much I want to tell you. That's why I came here specially."

Kili shrugged then continued in a sharper tone of voice.

"Your side plans to destroy Yggdrasil's mind, right? I heard the gist from Tia just now."

"Y-Yeah..."

Since Tia already told her, it was pointless for me to hide it, so I nodded in admission.

"I will offer you honest advice. As things currently stand, your plan will still fail no matter how hard your side tries."

"What—Why would you know...?"

"I know. Because even earlier than you guys, starting long ago, I've been searching for a way to defeat Yggdrasil."

Kili interrupted me and replied.

"Huh...?"

"Yggdrasil can interfere with dark matter. You should know this since you fought it at Midgard, right? In other words, Yggdrasil is the natural predator of 'Black' Vritra—Mother."

Kili had confessed to me in the past that she was a being created from Vritra's dark matter. Hence, what she said just now was meant literally.

To Tia and John who did not know the truth, it probably sounded like Vritra was something like a mother for giving Ds the power to generate dark matter, but Kili was actually Vritra's daughter in a real sense.

"Twenty-five years ago, Mother went missing in order to escape from Yggdrasil. This is the truth of Vritra's disappearance."

"What... Are you for real?"

I could not believe that she had told me the answer to this mystery, still debated all over the world, so easily. I asked her hoarsely.

"Yes, I'm not going to lie. Honestly, I originally wanted to pique your interest with this fact, to serve as a bargaining chip... But if I keep my cards hidden, you won't be able to understand the current situation correctly, so today, that's why I'm telling you many other things you want to know."

"The things I want to know..."

There were too many. I did not know which of them she was referring to.

"You are very curious about my relationship to Hekatonkheir, right?"

"Y-Yeah... Because you also addressed Hekatonkheir as mother, Kili."

"I'll answer this question of yours. In the past, while hiding from Yggdrasil, Mother also controlled an avatar created from dark matter to take action, and that avatar is precisely 'Blue' Hekatonkheir. Although half of it is materialized, it's probably quite similar in nature to the fictional armaments of you Ds."

"Hekatonkheir is Vritra's avatar... fictional armament."

I muttered blankly, but my mind agreed with it partially.

The reason why Kili had addressed Hekatonkheir as mother in the past and why Hekatonkheir had exhibited astounding regenerative powers—If it was Vritra's avatar made from dark matter, all these questions were easily explained.

"Yes, by the way, I served as something like a relay to link Mother to Hekatonkheir. Through the dragon mark on my body that's linked to Mother, Hekatonkheir could materialize on the spot or replenish its dark matter."

"Relay...? Don't tell me that when Hekatonkheir appeared at Midgard, it was also—"

That time, Hekatonkheir had appeared in Midgard without any warning at all. Even the alarm was sounded after Hekatonkheir showed up. I finally understood why.

"Just as you think, Hekatonkheir appeared through me. But Mother used biogenic transmutation to change my dragon mark in order to make me into Hraesvelgr's mate, so I can no longer serve as a relay."

And the chosen one ended up not being me, how silly of Mother—Kili shrugged.

At the Principality of Erlia, Hraesvelgr chose Firill instead of Kili. Calling herself an "imitation," Kili looked quite heartbroken when she was not chosen... Right now, I could see her "in pain" slightly.

"Because my link to Mother has been severed, altering my dragon mark again is impossible. Thus, I'm free. Prior to that, I've always acted according to Mother's orders. Finding a way to eliminate her natural predator, Yggdrasil, was also one of my assigned missions, so regarding strategies against Yggdrasil, I have an edge held by no other person."

Kili spoke in fierce tone of voice and looked at me solemnly.

"Yuu, listen carefully. First of all, based on the current situation, approaching Yggdrasil is already difficult enough. Something on the level of jamming won't be able to stop Yggdrasil's interference. It will get rapidly analyzed and neutralized. Even if you the plan succeeds in destroying Yggdrasil's mind, a new core consciousness will end up getting built. That's inevitable because the physical body is not destroyed."

Kili eloquently dashed our hopes to pieces.

"Gah... If what you say is true, what should I do—"

Even if someone said it was impossible, in my situation, all I could do was fight. Yggdrasil's power to control was increasing. Once I got controlled, even trying to fight would be impossible.

"There does exist a solution to problems in the plan. But whether you'll be able to obtain that solution—I don't know."

Kili shrugged and remarked coldly. She seemed to glance at Tia for just an instant.

"By this point, are you still trying to act dumb?"

"You've got it wrong. I can only say this at the moment. In any case, please don't insist of fighting despite knowing there is no chance of victory. That's all I want to say."

Kili looked away from me and faced John.

"The job is done, let's retreat."

John seemed unable to hide his shock at what Kili had said, but he pulled himself together and nodded.

"G-Got it. Then Captain—I will take my leave now."

After bowing respectfully, John chased after Kili. They seemed to be moving towards the exit of the Castle of Mirrors.

"—Oh, one more thing."

Just as they were about to exit the hall, Kili stopped and looked back at me.

"What is it?"

I stayed on maximum alert but Kili spoke seriously:

"The lab where you're staying... is a bit unusual. Compared to other facilities, the level of security measures is quite extraordinary. There are many areas locked by administrator access."

"What do you mean...?"

I asked, not really understanding. Kili narrowed her eyes and said:

"In other words, the facility's highest authority, the director, keeps quite a large research area to himself alone. I sense a dangerous presence, so please be careful."

Leaving that warning behind, Kili disappeared with John on the other side of the passage, leaving for real this time.

Areas occupied solely by the lab's director, Miyazawa Kenya.

Indeed, I felt inexplicable uneasiness in my heart. In addition, the many secrets revealed by Kili kept circling in my mind.

Of course, there was no guarantee that everything Kili said was the truth. She might have told lies for the sake of misleading me.

The more I thought, the more questions popped up nonstop. If Hekatonkheir was Vritra's fictional armament, then Vritra's intent was the reason why Hekatonkheir went for a suicide explosion with Yggdrasil at the Germany-Denmark border.

Kili had not mentioned this incident at all. Speaking of which, her reason for infiltrating the lab was still a mystery.

"Yuu...?"

While I was lost in thought, Tia tugged my clothing and called to me.

Oh—

I came to my senses, patted Tia's head and smiled at her.

"—Anyway, let's get back to the girls. They must be worried."

Scrutinizing what Kili had said should wait until I had discussed with everyone. Agonizing over it alone would not help. This was the lesson I had learned from past experience.

"Hmm..."

Tia's reply lacked energy. I sensed that she was also troubling over something.

What exactly did Kili say to her in my absence...? Although I felt extremely curious, it looked like I should not force the issue for now.

I'll try asking her after she calmed down.

"If you're tired, do you want to sit on my shoulders?"

I made this suggestion, hoping to cheer her up slightly, but Tia looked up with a smile.

"No need, Tia is fine! This is better, let's go, Yuu!"

Holding my right hand, Tia started to walk.

Choosing to hold hands instead of sitting on my shoulders, she pulled me forward.

Thus, we walked in the opposite direction from Kili and John, back to the entrance of the Castle of Mirrors.

The mirrors facing one another showed reflections of Tia and me, looking almost like travelers lost in alternate dimensions—

Chapter 3 - Invading Tempest of Green

Part 1

Due to the unexpected incident at the amusement park, we—the students of Brynhildr Class—returned straight to the research lab without taking any detours.

Then Shinomiya-sensei joined us and I told everyone what I had heard from Kili.

"The reason for Vritra's disappearance and the truth of Hekatonkheir—Although it is very interesting information, there is no proof. It would be dangerous to believe her completely."

After the sharing of information, Mitsuki proposed caution.

The venue was Mitsuki's room again. Like last time, I listened to her speak while leaning against the wall with the window.

"However, Kili's words cannot be ignored. I have asked NIFL, hoping they could verify the effectiveness of jamming... I received their response just now. The result is just as Kili said. Jamming's effects lasted only momentarily and was quickly neutralized."

Shinomiya-sensei replied gravely. She had stayed at the lab today, probably to contact NIFL.

"In that case... Approaching to attack is currently impossible. Furthermore, if what Kili-san said is true, then even if the plan succeeded, Yggdrasil still cannot be defeated."

Lisa spoke tensely.

"But we can't do nothing just because failure is possible!"

Iris protested urgently.

"...Iris is right. I believe we must do what we can at the moment."

Firill calmly supported Iris' stance.

"In that case, given the current situation, the only choice is still to strengthen Mononobe-kun's cooperation with Ren. You two have grown quite close today, so let's try making a fictional armament again right here."

Saying that, Ariella pushed Ren's back, bringing her before me.

Ren looked up at me slightly nervously.

"Then let's try it."

"Mm."

I said to her and Ren nodded.

Fictional armament—Siegfried.

I generated the fictional armament shaped as an ornamental gun. Ren placed her hand on the gun.

Dark matter instantly flowed in, causing Siegfried to expand and distort in shape.

"...!"

If I lost control at this point, things would end up the same as last time. Hence, I focused my thoughts and transmitted my imagination to the fictional armament, correcting Siegfried's shape that was twisting unnaturally.

My thoughts were transmitting to Ren's dark matter more easily than before.

—So dark matter really consisted of fragments of the mind.

Growing closer meant understanding each other.

I knew how to transmit my thoughts to Ren and Ren knew how to receive my thoughts.

Naturally, this was only on the level of a "feeling," but it was the difference between heaven and earth compared to when I understood nothing. In that case—

However, I must have lowered my guard just as success came into sight.

Siegfried suddenly collapsed into bubbles just as it had expanded to roughly three times its size.

"Oh... What a shame. But I think this is a great leap in progress after merely a day."

Despite the failure, Ariella still applauded us.

"Indeed, all that remains is sustained practice, I suppose. Through repeated attempts, you should be able to master the key principles."

Lisa nodded in satisfaction. Since this was coming from Lisa who had trained similarly with Ren before, I could take this as: I'm finally at the starting line.

But amidst the slightly excited atmosphere, only Tia kept her head bowed silently.

"Tia?"

Feeling concerned, I called to her. Tia shook in fright then looked up.

"Eh, Yuu... What's up?"

"Oh, nothing much, but I think you're acting a bit strange."

Hearing what I said, Lisa also looked at Tia and frowned.

"Speaking of which, Kili-san took those forceful measures in order to talk privately with Tia-san. What on earth did you talk about?"

"......"

Tia's gaze wandered in hesitation in response to the question.

Seeing her reaction, I hastily interrupted.

"No need to force yourself if it's hard to talk about. But if you encounter any trouble, you can talk to me any time."

"...Tia understands."

Tia answered quietly and nodded.

Lisa sighed then reminded her, "It's a promise for sure, okay?"

"Well then, the night is getting late. Let us adjourn today."

Perhaps deciding there was nothing left to discuss at the current stage, Mitsuki announced the conclusion of the meeting.

Thus, we left Mitsuki's room and returned to our own rooms.

My assigned guest room was exactly opposite to Mitsuki's.

The furniture in the room consisted only of a bed, a desk and a closet. Then there was a bathroom with a toilet. A simple room. Compared to staying at the royal palace at the Principality of Erlia, this was quite cramped but to me, this type of room felt more reassuring instead.

Despite the temptation of lying on the bed, I held back my desire for sleep and returned to the corridor.

After making sure there was no one around, I went to Iris' room.

I knocked and she responded soon.

"Coming."

Iris opened the door and poked her head out.

"Can I have a moment with you?"

"—Sure."

With blushing cheeks, Iris nervously invited me into her room.

Iris was identical in layout as Mitsuki and my rooms, but there were all kinds of belongings scattered messily already.

"Oh, I'll tidy up straight away!"

"O-Okay."

I avoided looking while waiting for Iris to frantically stuff underwear and other articles into her bag.

"T-Thanks for waiting. Sit here, Mononobe."

Iris pulled out the chair at the desk for me then sat down on the bed herself.

"Thanks."

Seeing me sit on the chair, Iris spoke up.

"So, what's this about?"

Iris tilted her head and asked me. I answered:

"I wanted to explain what happened to you in more detail, Iris. In fact, I've confessed my secret to Ren."

In the beginning, only Iris knew my secret and now I was telling her that Ren was in on it as well.

"I see, hmm... I guess that's for the best. How did Ren-chan react?"

"Although angry, she was more worried about me. She said: 'Now isn't the time to be having fun in this kind of place. Hurry and go back to practice dark matter transfer.'"

"Ren-chan really is so kind."

Iris smiled gently and continued:

"So, how do you feel, Mononobe, now that you've gained such a kind little sister?"

Iris asked as though poking fun at me.

"Well... Umm, I'm really glad I can become better friends with her."

I chose my words carefully. Somehow, I got the feeling that things would be bad if I phrased things carelessly.

"Definitely. Your face looked so gentle when she called you Onii-chan."

"I-I didn't..."

"You can't hide it, because I'm always watching you closely, Mononobe, ah..."

Iris asserted confidently but went red as soon as she realized what her words meant. Feeling embarrassed too, I looked away.

"Don't suddenly say something so embarrassing..."

"Ahaha... Sorry."

Despite apologizing, Iris looked quite happy.

"What's with you?"

"Uh, somehow it makes me very happy to know that you get embarrassed by what I say, Mononobe."

Iris answered with her face red. Hearing something like that from her made it even harder for me to face her directly.

The conversation halted, making me conscious of the silence in the room.

But instead of being suffocating, this type of silence felt like a time of sweet comfort.

However, we could not stay like this indefinitely because I came for a different purpose.

After the battle against Yggdrasil at Midgard, I had not had a chance to spend time alone with Iris and talk properly, so I must tell her about that now.

"—Iris, there's actually something important I need to tell you."

I intentionally tensed my relaxed expression and spoke in a serious tone of voice.

"Eh? What is it?"

Seeing me like that, Iris prepared herself and asked me stiffly.

"As long as Ren can supply me with dark matter stably, the Yggdrasil battle plan should be possible to put into action. We can't know whether or not what Kili said was correct until we try it."

"Yeah.. We can't do nothing."

Iris agreed while listening to me.

"Also, once the battle begins, your Catastrophe will be a major force in the battle. Mitsuki and Shinomiya-sensei's battle plan will probably take your power into consideration. When time comes for the decisive battle, the principal will probably permit you to use Catastrophe, then even if you didn't want to, Iris, you'll probably realize it too."

"Realize what?"

Iris widened her eyes and asked.

—I already knew she was not aware, which was why I had to tell her personally using this opportunity.

"Iris, you used Catastrophe without going through dark matter."

"Eh... What is this about not going through dark matter—"

Perhaps it was hard to imagine. Iris showed a troubled look.

"During the Yggdrasil battle at Midgard, Iris, you used that red beam—Catastrophe—directly, which is why you weren't affected by Yggdrasil's interference. If it's your Catastrophe, Iris, I think you'll probably be able to attack normally even if you approach Yggdrasil's main body."

"Eh! Isn't that wonderful!? It means I can fight Yggdrasil head on! Maybe I might be able to defeat it on my own!?"

With an expression of joy, Iris exclaimed excitedly.

"N-No, it's uncertain whether you can fight alone since we don't know the scale of your Catastrophe or how many times it can be used. And even if Yggdrasil's body could be destroyed, it'll just transfer its core consciousness somewhere else."

"Oh right... After destroying the body, you need to attack Yggdrasil's mind. But because dark matter will be stolen, you can't approach as the key person... Hmm, what should we do?"

Iris crossed her arms and started to rack her brain, but her reaction was completely different from what I expected.

"Mitsuki and Shinomiya-sensei are probably thinking about how to approach Yggdrasil, so leave it to them for now. Rather... Aren't you afraid, Iris?"

"Afraid? Why?"

"You used Catastrophe directly without transmuting dark matter, you know? It's unprecedented. If Asgard learns of this, Iris, you might be seen as a dragon."

"Huh..."

Perhaps she realized only after I mentioned it. Iris looked at herself in surprise.

"...But I'm not a monster like Basilisk or Leviathan, right? I won't destroy cities or do bad things, you know?"

"I know that, but Asgard and NIFL will designate dangerous Ds as disasters and allow them to be executed. If those guys found out about you, they'll definitely see you as a threat, so under all circumstances, do not openly disclose the fact you can use Catastrophe directly."

I stared into Iris' eyes and warned her in a strong tone of voice.

"O-Okay, I got it. But... Then that means I can't use it in front of other people?"

"Although there's a risk, you can say that you instantly transmuted the dark matter, then it should be impossible to tell the difference."

Iris seemed quite unsettled. I pondered while replying to her.

Dark matter was almost unseen if it was transmuted at the same time as it was generated. Even when watching from the side, it should be impossible to tell.

If Iris used Catastrophe again while inside Yggdrasil's interference range, the secret might get exposed... But since Mitsuki was unaware of this, she probably would not devise a battle plan that would lead to such a situation.

"That's good to know... I thought I can't fight alongside everyone else anymore."

Iris breathed a sigh of relief. Compared to herself, she seemed more concerned about others.

Thud. Iris dropped her upper body onto the bed and raised her right arm towards the ceiling.

"However, a dragon huh... Mononobe, do you think I look like a dragon?"

"No, not at all. You're human, Iris."

I asserted and Iris smiled.

"Thank you, but I think I've lost a bit of confidence."

Iris seemed to gradually realize the gravity of the situation. Her voice sounded a bit melancholic.

"Don't worry, Iris, you haven't changed one bit."

"Really? Then... please look carefully to confirm."

Iris got up from the bed.

"You're asking me to confirm...?"

"I want you to help me confirm through your eyes, Mononobe, that there's nothing strange about me. Please."

"O-Okay."

Iris begged me seriously and I stood up from the chair.

I circled around Iris, who was dressed in school uniform, observing her from all directions.

Dazzling silver hair, lovely facial features, slender arms and legs, pale skin, a bulging chest that could be seen even with the uniform, a slender waist—

Taking a good look again, all of her was still so attractive. I felt my heart rate rise naturally. The color of skin exposed between her miniskirt and kneesocks attracted my gaze compellingly.

"How is it?"

After seeing me circle her once, Iris asked me.

"Even if you ask me..."

Too conscious of her, I could not even look her in the eye.

"What? Don't tell me there's something weird?"

Seeing me hesitant, Iris got frantic.

"No, not at all, my only comment is... umm, Iris, you're really so adorable..."

I endured my embarrassment and replied. Iris' face instantly went boiling red.

"A-Adorable... Sheesh, that's not what I want to hear about!"

"Oh, of course, there's nothing weird, okay?"

I frantically added but Iris glared at me with a blush.

"Honestly?"

"I'm not lying."

I nodded but Iris did not seem satisfied. She looked at her own body.

"On further thought... To confirm beyond a doubt, I have to undress... Right?"

Iris spoke as though in a trance and started untying the ribbon on her uniform.

"W-Wait! That will be bad no matter how you look at it!"

I frantically stopped Iris.

If I saw her naked body under these circumstances, I was not confident I could hold myself back.

"But... I'll be too worried to sleep unless we confirm beyond a doubt."

Iris' expression was a mixture of shyness and unease. She looked at me with pleading eyes.

I desperately racked my brain, thinking what to do and finally came up with a compromise.

"Then just show me your dragon mark. A D's change usually shows on the dragon mark. It's not just when chosen by a dragon. Scars appeared near my dragon mark when I gained the abilities to replicate Leviathan and Hraesvelgr's powers. So I think there's no need to look at other places if there's no change in the dragon mark."

I said all that to Iris in one breath.

"R-Really?"

"Yes."

While she was intimidated by my vigor, I nodded with a serious expression to make Iris accept my suggestion.

"...Got it, then you have to look carefully."

With slightly trembling hands, Iris grabbed her shirt and slowly opened the front.

Pale and smooth skin was exposed to the outside air. Iris' abdomen was presented before my eyes.

My gaze was drawn to the navel's depression and the lines of her waist. I could not speak for a moment.

"M-Mononobe, quit staring at my belly and look at my dragon mark."

Iris spoke with her face bright red. Perhaps due to shame, her skin was sweating slightly with a slight red flush.

"S-Sorry."

I hastily took a kneeling posture, bringing my face near her dragon mark located on her flank.

"Kyah... Y-Your breath is touching me."

Iris shook.

The sweet fragrance from her skin was shaking my sanity but I mustered all the self-control in my heart and observed her dragon mark closely.

"There's nothing unusual."

I reported as calmly as possible.

I had seen Iris' dragon mark multiple times. Meeting Iris for the first time when she emerged from the sea naked and during the time when Leviathan targeted her. Since those were shocking situations, the memories were very vivid.

Hence, I could assert clearly that its size and shape had not changed.

"Don't just look, touch it."

However, Iris still felt worried and said that.

"You want me to touch it... C-Can I?"

"Yeah."

Iris answered in an almost inaudible voice.

Despite the hesitation in my heart, I still reached for Iris' dragon mark, touching her tender skin with my fingertips.

"Mmm..."

The sweet voice leaking from Iris' lips made my spine tremble.

"Ah—ya..."

I stroked my finger along the dragon mark. Iris seemed to squirm from the ticklish feeling.

"Mmmmmm... Ah—Ahhh!"

Seductive moans were shaking my eardrums. Iris' pale skin was showing a faint red flush.

The texture of the dragon mark was no different from normal skin, hence, I did not notice anything unusual.

"I-It's okay. Nothing weird."

Despite feeling a numbness in the depths of my mind, I still managed to maintain my sanity and speak.

"I see... Thank you, Mononobe."

But just as I was about to withdraw my hand, Iris placed her hand on top of mine.

"Iris?"

I looked up at her in surprise, meeting her passionate gaze.

Badump—My heart instantly jumped intensely. I could not take my eyes off Iris.

Thus, we gazed at each other. I stood up from my kneeling posture, reversing the height gap between our gazes. Iris looked at me with a feverish expression.

My heart sped up. Iris held my hand with our fingers interlocking and leaned herself against me.

Touching me with her scorching body, that soft sensation was gradually eroding my sanity.

My mind went blank, unable to think.

"Mononobe..."

Our face drew close naturally, our breaths mixing together, lips—

But just at that moment, my portable terminal rang.

"!?"

Iris and I came to our senses and separated in a panic.

"S-Sorry, I think it's a phone call."

"Oh... Umm, I'm done now, so you don't have to keep me company. That might be an important call, so pick it up, Mononobe."

Iris said to me in a fluster.

"Got it, then I'll go back to my room first."

"—Yeah, goodnight."

Iris waved and I said goodnight to her before hurrying back to my room.

The portable terminal kept ringing. The caller ID read unknown.

—This pattern, Major Loki again?

While recalling the face of my former commanding officer who always called at annoying times, I pressed the button to pick up the call. But the voice I heard did not belong to the person I expected.

'Sorry for disturbing you this late. Are you free right now?'

"...This voice... Are you Director Miyazawa?"

I called out the name of Ren's father and the director of this lab. Although portable terminals were capable of video calls, there was only a voice with a dark screen this time, so I could not check the face.

'Yes, I've got something to ask you privately, which is why I called you.'

"How do you know my phone number...?"

'Something so trivial is easily found out given my status. Putting that aside, could you take the elevator now? Once you enter the elevator, it will automatically take you to my current floor. Let's leave the details until then.'

"How can you decide on your own—"

While the director spoke on his own, I could not help but frown.

'Then I will be waiting for you.'

Ignoring what I said, he hung up.

"What the heck is this...?"

I had no reason to humor him. Normally, one should ignore this kind of rude request, but—

I recalled Ren's past that Ariella had told me today.

She said that Ren had given up talking all because of Miyazawa Kenya.

Although I wanted to tell him off, I already knew that scolding him would have no effect.

However, through interacting with him, perhaps I might be able to do something for Ren.

Thinking that to myself, I left the room and made my way to the elevator.

Part 2

I entered the elevator and it descended automatically, opening its doors at the fourth floor underground.

What appeared in front of me was not a corridor but a vast laboratory. I could see Miyazawa Kenya's figure in a lab coat in the center of the room.

"Thank you for coming, Mononobe-kun."

He smiled cordially, still with ruffled hair and stubble around his mouth.

"What exactly do you want, calling me out alone?"

I asked warily.

Kili's words flashed through my mind. This lab's security measures were unusually strict with a majority of areas apparently occupied solely by the director.

This was the fourth floor underground, which was quite deep considering the elevator displayed showed a lowest level of five floors underground. Since there were no other researchers in sight, perhaps this floor was one of the places where only he had access.

"Just as I mentioned earlier, I have a personal favor to ask. I'd like you to assist in my research... A formal request would necessitate reporting the research to Midgard, which would be a tad inconvenient."

"I don't want to assist in that kind of shady research."

I refused readily after hearing his request. As expected, it was nothing good.

"Don't jump to conclusions. This proposal is in your interests too. Before the showdown against Yggdrasil, wouldn't you like to confirm Ether Wind's effects properly?"

"...What do you mean?"

Not hiding my suspicious attitude at all, I stared at his hollow smile.

"Whether the Ether Wind you create can actually cause souls to manifest, I'd like to confirm this. But the most effective verification experiment needs human cadavers. On the other hand, Midgard refuses to assist in or carry out that type of experiment due to concerns about the outside world's perceptions. Hence, my suggestion is: why not test it out secretly here?"

Miyazawa Kenya fluently explained his aim.

"What... Don't tell me—"

Speechless, I looked around the vast laboratory.

"Indeed, there is a cadaver here, but don't think too much about that. All you need to do is release Ether Wind at the specified location and observe the result."

Without any change in expression, he nodded nonchalantly in admission.

True, this was an Asgard lab. It would not be strange to have cadavers for research samples. I had heard that there was a system for transporting unidentified corpses for research use, so it might not be illegal... Probably.

"Risks are very high if you enter a battle without confirming effects first. In the event of failure, not only you but also your teammates will face danger. That isn't something you hope for, right?"

Seeing me in thought, he continued to persuade.

".......Fine."

After some hesitation, I nodded in assent. Although I was reluctant to let him get his way, I did not want to give up on the chance to confirm Ether Wind's effects. On the battlefield, minor differences could mean the difference between life and death. I could not refuse any chance to lower chances of Iris and the girls getting into a crisis, no matter how small.

"Okay, thank you, then let's get started. Come to this side."

Miyazawa Kenya looked delighted and rapidly walked over to the inner side of the lab where there was a partition. He started operating a control panel next to it.

"What's inside?"

I caught up to him and asked. The partition began to open with a heavy sound.

White mist and cold air flowed towards us from the gap.

"You'll know when you see it."

He answered briefly and went inside without waiting for the partition to open completely. I had no choice but to follow. The inside of the partition was like a fridge. The cold air swirling underfoot was making me shiver.

It was quite dark with the only illumination being the lighting shining in from the lab. In the center of the floor, covered with cold white air, there was a metallic rectangular box.

Several tubes extended from the box, connected to devices of unknown purpose, installed on the wall.

"I'd like you to scatter Ether Wind around that coffin."

Miyazawa Kenya pointed at the box in the center of the room.

"Coffin...? So inside that box is—"

"Yes, a cadaver."

He answered simply then urged me with his gaze.

His attitude basically said "I've already said everything that needs explaining."

But the heavy security made me wary.

Was that coffin really containing an ordinary cadaver?

Clearly just a cadaver for experiments, but placed under such heavy security, it did not feel right. If this was a storage for research samples, then having just a single cadaver would be very unnatural.

However, even if I continued to question, he would not give me the answer.

Fictional armament—Siegfried.

Anyway, my only choice was to do it. Generating dark matter, I shaped it into an ornamental gun.

I heard him gulp beside me.

I glanced at him sideways to see him staring at the coffin.

Although I could sense an unusual impression from him, I still pulled the trigger of my fictional armament.

"Ether Bullet."

Pouring in all the dark matter in the fictional armament, I fired the bullet. Siegfried vanished while shooting. The fired bullet transmuted into Ether Wind on the coffin.

The golden particles exploded and covered the coffin's surroundings.

Immediately, a faint outline came into view.

"Wow!!"

Miyazawa Kenya cheered.

Seeing that phenomenon, I held my breath and observed the situation.

The originally ambiguous outline gradually became distinct, to the point of showing a figure.

It seemed like... a woman.

But just as details became discernible, the golden particles rapidly faded. Immediately, the surfacing image also vanished.

Was that... the soul of the person resting in the coffin?

But since I did not know who was lying in the coffin, I turned my gaze to Miyazawa Kenya.

He should know the identity of the one inside the coffin. Given who he was, he should be able to make some sort of judgment even from that kind of outline.

"Haha... Hahahahaha!"

But I was surprised when I saw his face.

With eyes widened, he was in such rapture that his entire body was shaking.

"Ahhh... Rena, Rena... I knew our inferences were correct. Mononobe-kun, could you increase the density of Ether Wind? I'd like to see if it's possible to communicate with the manifested soul!"

"N-No, this is my maximum generating capacity, raising it requires..."

Feeling pressured by his forcefulness, I answered.

"I see... Then I need to enlist other's help—Oh, but that has its difficulties. No, it's fine, thank you. It is enough to confirm the existence of souls for now. I must hurry and finish my research... With that, surely..."

He muttered emphatically while staring at the coffin with fervent eyes.

"Umm, who was the woman just now? You mentioned the name Rena... Is that her name?"

But just as I asked, he suddenly stopped muttering to himself and stared at me darkly.

"—You have no need to know. You ought to be satisfied with verifying the practicality of Ether Wind, right? Things are done here. You may return."

Coldly refusing to answer, he drove me out of the cold room and closed the partition.

"Oh wait, before I head back, I'd like to ask one question. It's not about research."

While he was driving me away to the elevator, I asked a question I had decided a while ago that I must ask no matter what.

"Are you actually uninterested in Ren? If possible... Even for just a moment, could you act like a father to her? Ren is probably just afraid. She doesn't hate you. Even now, she still cherishes her memories of family... So—"

However, he pushed me into the elevator expressionlessly and told me in a calm voice:

"Regrettably, I am very busy and can't fulfill your demands. Thank you for assisting in my research. I might ask for your help again, so I look forward to your cooperation when the time comes."

"Ah—"

Without listening to my answer, he pressed a button from outside and closed the elevator doors. Like how I arrived, the elevator moved automatically.

Although I expected this, it turned out to be a waste of effort after all. I did not feel like he was listening to me at all.

In the end, I did not manage to do anything for Ren. I sighed and looked up the gradually rising floor indicator.

All I could think of was the female figure appearing due to Ether Wind.

Who could that person be?

But no matter how much thought I put into it, I could not know right now. The dissonant unease in my heart did not go away. I pressed my right hand against my left arm's cast—

Part 3

After breakfast the next day, Ren and I decided to formally start practicing the transmission of dark matter.

Our training location was the helipad on the roof.

Ren's dark matter generating capacity was quite massive. If the entirety of that dark matter was used, it would make a fictional armament dozens of meters in size. The lab did not have any spacious training site like in Midgard, so our only choice was outdoors.

The lab building was the tallest structure in the area, so there was no worry of getting seen by ordinary people from the ground.

"What fine weather we have today. It's very sunny and visibility gives us a view of distant scenery."

Serving as our coach, Lisa accompanied us and commented while looking out at the scenery.

Although the sea breeze blowing from Tokyo Bay was a bit strong, the sunlight was very comfortable.

Without nothing to block us, the view was quite magnificent. The scenery of dense buildings filling up the entire land seemed to pressure the viewer.

I turned my gaze. Mount Fuji's snow-covered peak entered my view and next to it was—

"So Yggdrasil is visible even from here."

The outline of the giant tree, even taller than Mount Fuji was vaguely visible.

"Mm."

Hearing me, Ren nodded with a stiff expression in response.

"Because it is 5000 meters tall. Now that I look at it again, it is truly an astounding size."

Staring at Yggdrasil afar, Lisa shrugged.

"So Tia and everyone will be fighting that kind of thing..."

Accompanying us to watch, Tia commented uneasily.

I thought she would cheer up after one day but her expression still seemed gloomy.

"But since the trunk is relatively narrow, it might feel less intimidating than Hekatonkheir."

Here to watch together with Tia, Iris remarked, bringing a wry smile to Lisa's face.

"You definitely won't be able to say that once you get near."

Ren, Lisa, Tia, Iris and I, the five of us were the only ones at the helipad on the roof.

Mitsuki, Firill, Ariella and Shinomiya-sensei were strategizing. Iris and Tia had nothing to do because they could not participate.

Their ways of thinking leaned more towards intuition and were unsuited to discussions based on theory and logic.

"Left alone, Yggdrasil might grow further. We have to train immediately to defeat it before that happens. Mononobe Yuu, Ren-san, are you ready?"

Facing us, Lisa confirmed.

"Yeah."

"Mm."

Ren and I nodded and started to practice transferring dark matter.

The same as what we did yesterday.

Ren placed her hand on my summoned fictional armament and poured in dark matter.

To prevent the expanding Siegfried from collapsing, I controlled as much as I could, stabilizing it while gradually growing its size.

The fictional armament expanded like a balloon. Since this was before transmutation, it was almost weightless. Even after surpassing palm-size, as long as thoughts were transmitted successfully, holding it up was easy.

However, it collapsed even earlier than the attempt last night. I failed to control Ren's dark matter. Losing stability, the fictional armament turned into bubbles and disappeared.

"—Pull yourself together. Are you not concentrating enough?"

Watching from the side, Lisa scolded harshly.

Perhaps she was right. Seeing the female soul in Miyazawa Kenya's lab and Tia's gloominess was affecting my concentration. Also, I was distracted by Iris watching nearby.

Last night, if Miyazawa Kenya had not called, what would have happened? Somewhere in a corner of my mind, I was thinking weird stuff like that.

"Sorry, I've got too many random thoughts. Please let me try again."

I apologized to Lisa and Ren.

"Onii-chan?"

Ren looked at me with worried eyes.

"Don't worry, I'll focus this time and only look at you, Ren."

I drove away all useless thoughts from my mind and stared straight at Ren's face.

"...Mm."

Ren looked away slightly embarrassed and nodded.

Since her father refused to listen to her speak, Ren had given up talking.

Then I must not miss any of her voice.

—If Ren's mother were still alive, Ren would probably love to talk more.

Although I believed that, such a hypothetical future was meaningless, so I prepared to switch mindsets.

But at this moment, a certain idea flashed across my mind.

Back when his wife was still alive, Miyazawa Kenya used to be a father who took his daughter to an amusement park.

Did he end up like this because his wife was too precious to him?

Perhaps—

I looked at Ren's face carefully from up close.

"...? Onii-chan?"

Ren tilted her head, somewhat troubled.

"—No, it's nothing. One more time, let's begin."

Since it was a spur-of-the-moment idea, I temporarily hid my doubts in the depths of my heart.

Lisa, Iris and Tia were nearby. Even if I wanted to discuss with Ren, it was not something to talk about in front of others.

Deciding to find a chance later, I formed my fictional armament in my right hand—

Practicing repeatedly with Ren, I gradually got the hang of it.

Initially, expanding my fictional armament to triple its size was the limit, but by the time noon came around, I could already create a fictional armament on the scale of several meters.

Even so, the success rate was still below 30% and I was still unable to control all of Ren's dark matter. Currently, the amount of Ren's dark matter I could use in my fictional armament was probably one-tenth of her maximum capacity, quite far from the goal.

Although we needed to continue training, a task demanding focus would sap mental strength, accumulating fatigue. Seeing my stamina quite depleted, Lisa asked us to stop.

"—Take a break for now and have lunch. You both seem exhausted, so let me go buy something for you."

Seeing Ren and I sitting on the floor in exhaustion, Lisa smiled wryly and offered.

As the provider, Ren had tried many different things to make her dark matter easier for me to control, which was why she had tired herself out significantly.

"Thanks Lisa, I'm counting on you."

There was a vendor corner in the lab's dining hall, which should sell stuff like onigiri and bread.

"Mm."

Ren lowered her head and bowed to thank Lisa.

"The weather is nice, so I'll go invite Mitsuki-san and the others to eat on the roof. Iris-san, Tia-san, let us be on our way."

Lisa called to the two observers but did not get a response.

The two girls were sitting in a warm spot under the sun, leaning against each other, sleeping comfortably.

"...Looks like they are enjoying an afternoon nap. No helping it, I shall buy lunch for everyone."

Lisa shrugged in exasperation and head to the stairwell.

The wind blew across this roof that had become quiet. Staring into the cloudless sky, I saw a vast stretch of blue.

Phew—Feeling as though I was expelling fatigue from my body, I exhaled deeply.

"Onii-chan."

Ren immediately spoke to me.

"What is it?"

I asked and Ren took a deep breath before asking me with her voice:

"......A-Are you okay?"

Surprised that Ren did not communicate by typing on her terminal, I reacted a bit slowly.

"Y-Yeah, I'm okay. Although I'm a bit tired, I'll recover my energy after eating lunch."

I answered this way to reassure Ren but she shook her head.

She took a deep breath then asked a moment later:

"Not talking about that...... Left arm."

Ren turned her gaze to my left arm in its cast and showed an uneasy look.

"I see, you're worried about the time limit. Relax, currently, there are no signs of Yggdrasil's control."

"But...... Must hurry. I-I'll try my best."

This time, Ren told me immediately with a serious expression. Whether practicing the transmission of dark matter or getting closer to me, Ren was giving her all for my sake.

Feeling a sense of warmth spreading from my heart, I stroked Ren's head.

"—Thank you, I'll try my best too."

"Mm."

Ren nodded in response.

Although the conversation ended, this tranquility was refreshing for the body and mind.

Since Iris and Tia were napping, Ren and I were virtually alone. Perhaps now was the chance to confirm the idea that had occurred to me just now.

"Ren, I want to ask you, do you have anything like a family photo from before?"

"...?"

Ren stared in surprise at me in response to my abrupt question.

"Oh no, I was thinking you probably resemble your mother. For example, this beautiful red hair doesn't seem like Director Miyazawa..."

After I frantically explained my reason, Ren took out her portable terminal and showed a picture on the screen.

"Mm."

A tall redhaired woman was in the photo, together with a younger and more tidily dressed Miyazawa Kenya—along with a young Ren.

A Ferris wheel could be seen in the background. The photo was most likely taken when they visited an amusement park as a family.

"This is your mother, Ren?"

I confirmed with her and Ren nodded.

"Mm, Miyazawa, Rena."

Miyazawa Rena—That seemed to be Ren's mother's name.

I could not help but gasp. When Miyazawa Kenya saw the manifested spirit last night, he had mentioned the same name.

A human dead body kept under heavy security by Miyazawa Kenya. If it was someone special to him, was there a possibility it might be his deceased wife?

What surfaced in my mind earlier was this kind of unfounded speculation. But after hearing her name, my suspicions instantly increased.

I looked at the photo while recalling the female soul I saw last night, but I could not determine if it was the same person.

However, Rena-san in the photo really resembled Ren. Facing the camera were two similar cheerful smiles.

The young Ren, showing no signs of her current timid personality, was holding Rena-san's hand tightly.

"Ren must love Rena-san very much."

"...Mm."

With nostalgia and a bit of sadness, Ren nodded.

What should I do? Should I tell her my suspicions?

I felt hesitant but I had no evidence. And judging from the situation last night, I would not get an answer even if I questioned him. Besides, if my hunched turned out to be right, it might only end up hurting Ren.

But... If I did nothing, it would only maintain the status quo. If that really was Rena-san's soul, it might be the key to repairing Ren and Miyazawa Kenya's relationship. I could not give up on that possibility.

"Ren, I'll take you somewhere later. I'll pick you up tonight, so please wait for me."

I made my decision and spoke.

Let's take Ren directly to Miyazawa Kenya's lab to confirm.

Even using the current state of silent understanding, I should be able to produce more Ether Wind compared to yesterday.

If I told Miyazawa Kenya this, he would not say no, right?

However, if that really were Rena-san's coffin, then he might avoid letting Ren see it... But even if he refused, it would serve as a basis for judgment.

"...Mm."

Despite showing doubt, Ren still stared at me and nodded lightly.

After dinner that night I called Miyazawa Kenya on an internal line and got permission to visit.

Then I went to pick up Ren at her room and took the elevator again like last time.

The elevator descended to the fourth floor underground again. When the doors opened, I could see Miyazawa Kenya waiting in the lab already.

"I am very happy that you approached me to assist in my research, and today, Ren came along."

Looking at me and Ren, he smiled.

"...Mm."

Ren hid behind my back and looked at me uneasily.

"Please let us repeat yesterday's experiment together. I should be able to produce more Ether Wind than yesterday."

I stroked Ren's head to reassure her and said to Miyazawa Kenya.

"Of course, no problem. Come, over this way."

He agreed readily and led us to the partition inside the laboratory.

It looked like he did not mind showing Ren that coffin and the woman's soul.

Perhaps I guessed wrongly? Although I felt worried, it was too late to turn back.

With a heavy sound, I stepped into the inner side of the partition and saw the white coffin again.

"Mm..."

Ren was shivering from the cold air inside the room.

"Ren, I think you must have many questions... But I hope you'll lend me dark matter like we practiced today."

I spoke to Ren after generating Siegfried in my right hand.

Perhaps you might be able to see Rena-san's soul—I could not bring myself to say that. Because if things did not happen as predicted, Ren might be very hurt to have her expectations betrayed.

"Mm, I trust you."

Ren nodded and replied, putting her tiny hand on my fictional armament.

Instantly, Siegfried expanded rapidly, reaching a size of five meters.

"—Ren, stop. If it expands more, it won't fit in the room."

I barely managed to maintain the fictional armament's shape while telling Ren to stop. Although the room size was an issue, during today's practice, this was also the limit in weapon size. A moment of carelessness and the fictional armament would collapse, so it was impossible to sustain for a long duration.

Before it collapsed, I converted all of the dark matter contained in the fictional armament into Ether Wind.

"Ether Bullet!"

A giant bullet of dark matter shot out, turning into golden particles.

Not limited to the coffin's surroundings, the entire room was shrouded by shining particles.

"...!"

Since the particles filled the space densely, my body could not move and I could not make a sound.

This was the same phenomenon as when Hraesvelgr sealed our movements.

As soon as living humans were enveloped by these particles, they entered a state with their spirit sealed inside the physical body, preventing the body from moving.

Perhaps I had slightly misjudged the required amount. Ren and Miyazawa Kenya were frozen with surprised expressions on their faces.

Amidst such a high density of Ether Wind, a woman's silhouette appeared over the coffin.

Like drawing a picture, tiny particles gradually traced out an outline.

Gradually, the details of the face and her hairstyle could be discerned, but—

No...

She was not the Miyazawa Rena I saw in the photo Ren had shown me.

I could not tell the color of her hair, neatly cropped at shoulder length. Due to being made of Ether Wind, she was golden from head to foot. But judging from her Japanese facial features, her hair color was probably black.

She looked very young, similar to my age.

And somehow, there was a familiar feeling, she seemed to resemble a certain someone... That was the impression I got from the young woman in front of me.

The manifested soul of the girl stood expressionlessly without moving. Perhaps lacking consciousness, she simply stared blankly into space.

Even if we wanted to talk to her, our bodies were unable to move due to the excessive density of the particles.

Thus, time simply flowed by. As the particles gradually faded away, the girl's figure became fuzzy. By the time we could make a sound, the girl had already disappeared. I sighed.

"...So it's not Rena-san."

Due to excessive disappointment, I accidentally blurted my thoughts out.

Hearing me say that, Miyazawa Kenya went "ahh, I see now" in realization.

"Mononobe-kun, you originally thought that was Rena's coffin, didn't you?"

"!?"

Ren looked at me in surprise.

"...Yes, because when seeing that soul yesterday... You mentioned the name of Rena."

It was useless to hide it at this point, so I nodded in admission.

"Very regrettably, the coffin only contains an ordinary research sample. The reason I mentioned Rena's name was because we had researched Ether Wind together to confirm its properties. You've shown me an interesting phenomenon this time, and for that, I thank you."

Miyazawa Kenya thanked me dutifully. I looked away.

Thinking back, I recalled he had said "our inferences were correct." He was simply happy because his and Rena-san's research were proven to be correct.

"...Onii-chan?"

Ren tugged my clothing as though demanding an explanation.

"Sorry, Ren. I was originally wondering if I might be able to let you meet Rena-san's soul, that's why I brought you here, but my hunch was wrong."

I apologized to Ren, feeling sorry for her.

Immediately, Miyazawa Kenya smiled wryly and said to us:

"You are truly... considerate for Ren. By this point, rather than feeling annoyed, I have to respect you instead."

His words were filled with mockery, but I felt that rather than directed towards me, he was targeting himself.

"You probably hope for Ren and I to become an ordinary father-daughter pair, but that's already impossible. This might affect my research if I keep ignoring this problem, so let me make things clear right now."

Putting away his fake smile, he spoke with a serious expression.

"By saying impossible... Have you considered Ren's feelings?"

He sighed after hearing my question.

"I am a man unfit to be a father, having chosen research instead of my daughter. At the same time, I'm a terrible human being who has no scruples when it comes to research. Please don't harbor any expectations for someone like me."

"...!"

Ren gasped and gripped my clothing tightly.

Then Miyazawa Kenya spoke the decisive words to the tearful Ren.

"Listen carefully, Ren. I—cannot love you."

Ren looked up at him, dumbstruck.

"You bastard—"

I desperately suppressed the urge to punch him.

I regretted bringing Ren here so recklessly. I did not want her to hear something like that.

"...You."

Head down, Ren seemed to be saying something quietly.

"Ren?"

"......Hate...... you..."

Shoulders shaking, Ren kept repeating the same words in her mouth.

"If you have something to say, could you speak clearly?"

Miyazawa Kenya quietly urged her. Ren looked up and—yelled loudly.

"I hate you! I hate you the most, Father!!"

I heard Ren's angry voice for the first time, echoing inside the room. I stared in shock at her angry appearance.

Ren was glaring at her father directly. Feeling the gaze of those intense eyes, Miyazawa Kenya smiled.

For some reason, I could sense relief in his smile.

"Very well. Hate me. Go find love away from me. That way, Ren, you'll surely obtain happiness."

"I'm already have a lot of happiness! Because I have Onee-chan and Onii-chan, I don't want Father at all!"

It was an irrevocable falling out.

But in my eyes, this also seemed to be the first time these two people were speaking from the heart to each other.

"Then there's no problem. I will focus on research without anything to worry about."

"Suit yourself. I'll get close to Onii-chan as much as possible."

Saying that, Ren hugged my right arm tightly.

"R-Ren?"

Troubled, I called her name. Ren showed uneasiness on her face.

"Onii-chan... You don't want to be close with me?"

"Of course I want to."

I hastily reassured her. A smile instantly bloomed on Ren's face.

"...I'm so glad. You'll continue to be my Onii-chan from now on?"

Ren happily rubbed her cheek against my arm, asking me to dote on her.

"Do this kind of thing back in your rooms? You'll get in the way of research. Please leave."

Miyazawa Kenya spoke impatiently.

"...I don't need you to tell us to leave."

Pulling my hand, Ren walked towards the elevator.

Despite hearing cold words, Ren's expression no longer wavered.

Not only that, she seemed to have let go of certain hang-ups, showing a cheerful and refreshing expression.

I looked in Miyazawa Kenya's direction. He had already turned around.

"Onii-chan, thank you."

Ren thanked me while she walked.

"Huh? No, I didn't do anything deserving of thanks, right?"

Not only that, I accomplished nothing at all. It was a huge failure.

"Of course not, Onii-chan. I'm so happy you tried to let me meet Mother. And I got to argue with Father... This is good."

Ren shook her head and told me that.

"Ren..."

Because of me, because I had brought Ren here, their relationship was destroyed beyond repair.

Ren could not possibly feel no sadness. But even so, Ren did not cry. She still continued to move forward bravely. In that case, I should encourage her instead of apologizing.

"Okay, let's report back to Ariella that you gave that damn father a good tongue lashing."

"Mm."

Ren answered me with a smile.

Then just as we were about to take the elevator, a shrill alarm sounded in the lab.

"What's going on?"

Ren and I stopped and looked around.

Miyazawa Kenya ran over to the desk and picked up the internal phone.

"What happened?"

I heard him inquire the other side. I observed his situation for now, only to see him put down the phone and say to us:

"—Both of you, we have an emergency."

"Did something happen?"

Ren and I walked over to him.

Ren looked a bit embarrassed but now was not the time to be concerned about that kind of thing.

"Yggdrasil is apparently extending branches rapidly, expanding its interference range. In a few hours, this research lab and its surroundings will be subjected to electrical malfunctions."

"What... Why so suddenly—"

"Who knows. Perhaps it is making a preemptive strike before you can prepare yourselves fully. In any case, please head over to the main entrance on the ground floor. I will contact the other Ds and arrange a vehicle. You will get away from Yggdrasil as quickly as possible, because you will be unable to generate dark matter once you enter its interference range."

Even in such a situation, he calmly issued orders without any signs of anxiety.

"Can't you prepare a helicopter?"

"It's not that I can't but I wouldn't recommend it. Since all it takes is a tiny bit of interference to bring down a flight. The same goes for using transmutation to fly in the sky."

"...That's true. I understand. Then we'll be on our way."

I nodded in agreement. Then he said in a carefree tone of voice:

"Great, please do your best so that I can keep carrying out my research here."

Hearing that, Ren frowned and made a face at him then pulled me by the hand.

"...Onii-chan, let's go."

"Yeah."

I smiled wryly while following Ren into the elevator.

Part 4

"I'll drive fast so please secure your seat belts, okay?"

Starting up the van was the same middle-aged woman who had looked after us as the driver taking us to the amusement park.

Ren and I had met up with Iris, Mitsuki, Lisa, Firill, Ariella, Tia and Shinomiya-sensei at the entrance. The nine of us put on our seat belts as instructed and looked at one another with tense expressions.

Perhaps because it was just before bedtime, Lisa and Firill had wet hair. They probably happened to be in the bath and had to get ready in a rush.

"Shinomiya-sensei, developments have gone beyond prediction. What do we do next?"

Amidst the tense atmosphere, Mitsuki asked Shinomiya-sensei.

"Until we gather detailed information, we will escape east to distance ourselves from Yggdrasil. Once we ascertain the range of interference and rate of expansion with an accurate warning perimeter, we will switch to offense."

Shinomiya-sensei answered while operating the laptop on her lap. Perhaps she was in the middle of collecting information sent by Asgard and NIFL.

"True... We would be out of options if the tree branches extended without limit. Consequently, we must destroy Yggdrasil's extended branches from out of range, to push back the interference zone."

Lisa nodded and looked out the window.

It was currently 10pm and all dark outside. Amidst the dark scenery, outdoor lighting and the lights from windows flashed past instantly.

The electrical interference had evidently not reached this area but as soon as we entered the highway that ran along the shore, a massive congestion could be seen in the westbound lanes. Most likely, cars became stalled as soon as they entered the interference zone."

Although the eastbound lanes were busy too, the flow of traffic was moving at least.

"Pushing back the interference range... Then what? Maintain the status quo? Or... execute the attack plan?"

Firill asked about our future direction. Ariella responded:

"By this point, we have to go through with the plan, right? I think we need to destroy the enlarged Yggdrasil even if we cannot defeat it completely."

Mitsuki nodded in agreement with Ariella. Sweeping her gaze across everyone, she said:

"I agree. We will approach as much as possible to attack Yggdrasil's main body. Then after that, Nii-san will scatter Ether Wind if possible then attempt to destroy Yggdrasil's mind using the anti-dragon armament."

"—Understood."

Undeniably, we lacked preparation but our only choice was to do everything in our power.

Just as I made this decision, I felt a slight feeling of numbness across my left arm.

'—Neun.'

Yggdrasil's emotionless voice sounded in my mind. Surprised, I looked out the window immediately. The van had reached a gentle curving part of the highway which offered a clear view of Tokyo's night scenery.

Those countless electrical lights were gradually disappearing.

As though sliced off, the lights started to disappear gradually from the west side.

"Yggdrasil's territory seems to be approaching the heart of Tokyo. It feels as if... the city is gradually dying."

Lisa stared at the city that was slowly losing its lights and commented.

But I did not have the luxury of wallowing in sadness. To prevent my left arm from moving on its own as before, I held down my left arm firmly with my right hand.

I had a feeling that the principal's power of dominance was starting to be balanced out by Yggdrasil's interference.

"Onii-chan, are you okay?"

Ren asked quietly.

"Yeah, I'm currently fine."

I replied quietly not to let others hear.

Perhaps "currently" made her realize my situation. Ren made a serious face and touched my left arm.

"If possible... No, we absolutely must defeat Yggdrasil."

"Yeah, but I don't know if the transfer of dark matter will go smoothly..."

Since I still could not control all of Ren's dark matter, it was unconfirmed whether I was able to scatter enough Ether Wind.

"Don't worry about that."

However, Ren asserted in a voice filled with conviction.

"I already hate Father. Given now, I'll be able to think of you more strongly. My dark matter will definitely not reject you, Onii-chan."

"...Got it. I trust you."

"Mm."

Ren nodded at me.

I suddenly felt an intense gaze. Tracing it, I met eyes with Tia.

"...!"

Tia moved her lips and seemed to have something to say, but ended up saying nothing, bowing her head.

"Tia-chan, do you have something to tell Mononobe?"

Iris noticed Tia's situation and asked her gently.

"—Nothing much."

Tia shook her head and denied, but her voice was filled with heavy worry.

"Tia, I hope you'll tell me if you're worried about anything. It's very dangerous to enter a battlefield with doubts."

Worried about Tia, I said that to her but she silently shook her head.

Just as I was thinking I was finally friends with Ren, it became Tia's turn to become like Ren's former state. What should I do? I could not help but scratch my head.

In the end, without finding out what was troubling Tia, we made preparations to begin the operation.

Shinomiya-sensei made a call somewhere while operating her laptop. She ended the call and announced to us:

"I have asked NIFL to transmit their spy satellite's data to us, allowing us to monitor the electromagnetic wave anomaly zone surrounding Yggdrasil in real time—in other words, the range of its electrical interference. According to surveillance, the interference zone's expansion has greatly decelerated, currently moving at 30 km/h. Having pulled away sufficiently, this is the end of our escape."

After saying that, Shinomiya-sensei asked the driver to park the van somewhere nearby.

The driver replied affirmatively and steered into a parking area that happened to be within sight.

"Asgard and the Japanese government have reached an emergency agreement to obtain a permit for special measures against a dragon disaster. Thus, the paperwork is done for Ds to engage in combat. However, attacks causing casualties in residents or damage to cities are strictly forbidden."

While Shinomiya-sensei continued to speak, the van stopped in the parking area.

We got off the van and looked up at the night sky where Yggdrasil's branches were probably approaching.

"Since the sky is very dark, the branches can't be seen..."

Iris spoke uneasily. Lisa also looked out at the scenery visible from the highway and nodded.

"Perhaps that's part of its calculations. We've completely lost our bearing on where Yggdrasil's main body is, which was visible faintly during the daytime."

"...It's quite far from here to Yggdrasil. Or rather, I should say that simply approaching it will take a lot of time."

Firill spoke gloomily.

"Sniping distances will decrease during nighttime. Should we wait until dawn before attacking the main body?"

Mitsuki nodded in agreement with Ariella's suggestion.

"Yes. We will attack the branches from a safe distance while advancing towards Yggdrasil at the same time. Then we attack the main body in full force when dawn breaks. How about this for a plan?"

Mitsuki sought Shinomiya-sensei's opinion.

"It would be a wise course of action, but that would result in quite a protracted battle. We will rotate in teams to rest while advancing. Mononobe Mitsuki and Firill Crest will be Team 1. Ariella Lu and Ren Miyazawa will be Team 2. Lisa Highwalker and Tia Lightning will be Team 3. Without flying skills, Mononobe Yuu and Iris Freyja will stay on standby. Since your roles will be key during the assault on the main body, get fully rested while you have the chance now."

Iris and I nodded in response to Shinomiya-sensei.

"Yes, I got it."

"Understood!"

Then Shinomiya-sensei continued to issue orders.

"Each team should follow this division of roles. One person will generate lighting while the other attacks the branches by targeting visually. To prevent debris from falling on urban areas, I hope you will avoid using crushing and slashing attacks. Incineration or annihilation techniques will be the safest bet. If any debris falls, the one in charge of lighting should immediately provide cover."

"—Yes ma'am!"

Mitsuki and the girls answered in unison.

"Then the operation will immediately begin with Team 1. Put on your communicators and fly directly above the van. Eliminate all branches within visible range. From here, I will stay current on Yggdrasil's interference range in relation to your positions. Do not act on your own under any circumstances."

"Understood."

Mitsuki and Firill nodded affirmatively and put on their communicators.

"Brionac!"

"Necronomicon!"

Showing slight nervousness, they generated their fictional armaments. Even though this was a safe zone, it was impossible not to feel worried.

Having confirmed there were no anomalies with the generated fictional armaments, they exhaled in relief.

Then the two girls enveloped themselves in wind and flew to the sky.

Before long, bright light appeared in the air. It was the illuminating flare produced by either Mitsuki or Firill.

The light temporarily swept away the darkness of the night, causing Yggdrasil's branches approaching from the western sky to appear. Branching shadows resembling capillaries covered the entire sky.

However, a large part of the branches was blown away in an explosion exceeding the brightness of the flare. This was most likely an attack from Mitsuki's antimatter.

"Excellent, there is a minor change in the electromagnetic wave anomaly zone. The attack is effective. Stay where you are and continue attacking. I will contact you if there is a need to move. You two, stay directly above the vehicle at all times and don't lose us."

Staring at her computer screen, Shinomiya-sensei issued commands to Mitsuki and Firill through the communicator.

Then she turned her gaze to us.

"We will move the van while they push back Yggdrasil's interference range. Teams will rotate once every hour. This is an overnight operation, so please nap as much as possible in the van during breaks."

After receiving these orders, we boarded the large van again. Shinomiya-sensei sat down on the front passenger seat and gave detailed instructions to the driver.

"Let's sleep first as instructed."

"Yeah."

Ariella nodded in agreement with Lisa and closed her eyes.

"Goodnight."

"Mm."

Leaning against the seats, Iris and Ren started to nap.

I closed my eyes like everyone else but I did not think I could sleep.

'—Neun... Neun...'

Ever since the unusual feeling in my left arm just now, I kept hearing Yggdrasil's voice faintly.

Why was Yggdrasil so obsessed with me?

Also, what did Neun, this word meaning nine or ninth, refer to? Come to think of it, I did not know either why it chose me to make a deal.

If it was providing weapons data to exterminate the other dragons, then rather than choosing me, it would be better to pick one of the many girls with far higher dark matter generating capacities.

If possible, I wanted to ask Yggdrasil directly but calling to it on my own would be very risky. Perhaps it might seize the opening to invade my consciousness all at once.

I must not lower my guard tonight. Just wait for my chance to enter the stage.

I had experience with overnight operations back in NIFL and could maintain efficiency if it was just two whole days without sleeping. Hence, I set my approach and decided to rest only my body.

Opening my eyes, I met Tia's gaze again.

"G-Goodnight."

Tia frantically looked away and closed her eyes.

What on earth had Kili told Tia at the amusement park yesterday? That was still a mystery.

With many worries remaining, our long battle against Yggdrasil began.

Part 5

While gradually pushing back Yggdrasil's interference range, we began to move.

Driving off the congested highway, we moved westward along ordinary roads.

During this time, flares kept the night sky brightly illuminated while sounds of explosions shook the air intermittently.

So far, there were no accidents caused by destroyed remains falling down.

After an hour, Shinomiya-sensei ordered Mitsuki and Firill to return, then Ariella and Ren took their place to attack. Attacking the branches continually seemed to consume a lot of stamina. Leaning against their seats, Mitsuki and Firill quickly fell asleep.

If possible, I wanted NIFL's military to help out but faced against Yggdrasil's interference against machinery, even firing a missile was impossible.

Unable to take part in attacking, they seemed to be focusing their power on providing us with information and securing our route. Thanks to NIFL's vehicles performing skillful traffic management, we were able to move smoothly so far.

But nothing could be done about areas that had been devoured by the interference zone, or the city center with heavy traffic. Our van could only avoid those places and take slight detours to advance.

After another hour, the next day rolled in.

Returning, Ariella and Ren were thoroughly exhausted as one would expect.

"Tia-san, our turn to go."

"—Yeah."

Next to mobilize were Lisa and Tia.

Feeling bad that I was unable to take part in the shifts, I watched them depart.

Ariella and Ren also fell asleep quickly. I heard their breathing sounds with the rocking of the van.

'Neun.'

Yggdrasil's voice was gradually getting louder. The numb feeling in my left arm was also getting more frequent.

I felt poignantly that we were definitely approaching it.

Even though its influence increased the more we approached, I could not turn back. If I did not go, it would be impossible to defeat Yggdrasil. Sooner or later, my body would be taken anyway. Since what needed to be done remained the same, I would only cause unnecessary worry and alarm if I told Lisa and the others about the current situation.

The feeling of the principal's dominance over my left arm was gradually vanishing. Hence, I could judge the rate of invasion by the degree my senses recovered.

If in any event the final limit approached, I will end my own life before my entire body could be taken. I did not want to almost take another's life like last time.

Having committed my resolve, I kept my consciousness tense while keeping up my pretense of sleeping.

When the next hour-long shift was approaching again, the van stopped on the roadside.

"The road we originally planned to use seems to be congested. I will search for a new route. Standby here for now."

Shinomiya-sensei looked back from the front passenger seat and explained the situation to us.

At this moment, Lisa and Tia happened to return.

"Good work."

I greeted them, only to see surprise on Lisa's face. She probably expected everyone to be asleep. Tia went "Yeah... So tired" and smiled without energy.

"Mitsuki-san, Firill-san, rise and shine. It's your shift now."

Lisa shook Mitsuki and Firill's shoulders to wake them from their slumber.

"Yes... Understood."

"So sleepy..."

The two girls rubbed their sleepy eyes and got off the vehicle. Putting on their communicators, they flew into the sky.

Lisa and Tia sat down and prepared to rest.

But after a while, Lisa still kept her eyes open.

I was not planning to watch them that much but met Lisa's gaze at this moment.

"You—Don't tell me you have remained awake the whole time?"

Lisa leaned over and asked me quietly.

"No... I only just woke up."

I did not want her to worry so I denied it, but Lisa replied in exasperation:

"You're lying."

"H-How do you know I'm lying?"

"Of course I can see through my boyfriend's lies at a glance."

Lisa smiled mischievously then her expression turned serious.

"—Let us talk outside. Shinomiya-sensei, may we leave the van?"

"We are scheduled to remain here on standby for a while, so it's fine if you return before we move again, but don't stray too far."

Shinomiya-sensei answered without looking back from the front passenger seat.

Hence, Lisa and I got off the van and looked up at the night sky where the battle was taking place.

The flares were very bright. The moon and stars could not be seen. Explosions were annihilating Yggdrasil's branches. Warm wind brushed against our cheeks.

The area consisted of rural roads without pedestrians. No cars passed by either. Selecting open roads had apparently brought us quite far from urban areas. A giant mountain silhouette resembling Mount Fuji could be seen in the distance, but Yggdrasil's appearance was still indiscernible.

From the roof of the research lab, Yggdrasil could be seen on the other side of Mount Fuji—west of it. Shinomiya-sensei was most likely taking a detour around Mount Fuji on the north side in an attempt to approach Yggdrasil.

"There is a bench over there."

"A bus stop. Let's sit there."

A bus stop happened to be nearby so we sat down side by side.

"The operation is going smoothly for the time being. Yggdrasil is simply extending branches without doing anything else. Although this is admittedly advantageous to us, to be honest... The situation is very bizarre."

Looking at the bright explosions out in the night sky, Lisa spoke with unease.

"Maybe it's luring us over."

"The closer we approach, the greater the risk its main body would be destroyed. Yet it is still willing to face that risk...? You must have some basis for that idea, right?"

Lisa stared at me from extremely up close, demanding a certain answer.

"......Yeah, I'm probably the one it wants to lure. Starting a while ago, I've been hearing Yggdrasil's voice. Its interference affecting me is increasing, so to avoid giving it an opening to seize, I decided against sleeping."

I gave up resisting and confessed my condition honestly.

"What, why did you hide something so important!? In that case, wouldn't it be very risky to continue approaching Yggdrasil? We should at least have you retreat for now, right?"

"Maybe... But Lisa, the problem still can't be resolved even if Yggdrasil's main body is destroyed by you and the other girls' power, right? If Director Miyazawa is correct, it would only cause the core to transfer somewhere else. If things drag on longer, it will probably go beyond the point of no return."

I looked at my left arm's cast and replied.

"In other words, unless Yggdrasil is neutralized here, you will soon be taken over by it..."

"Probably. If I get the principal to help, total control might be avoided but in that case, my whole body will surely end up in a state like my left arm right now."

I pointed at my left arm that was currently deprived of feeling.

"That is truly a horrifying thought. I understand, then I shan't ask you to retreat, but... At this rate, even if Yggdrasil's branches could be eliminated, the interference from the main body still remains. Since jamming does not work, we will have to attack from afar... Will that be a problem?"

Lisa looked at me uneasily. She was worrying about my previous claim that Noah was unsuitable for sniping.

"I don't dare say there's no problem, but even so, I've no choice but to try."

I smiled wryly.

"...Indeed, then please succeed."

Lisa smiled and nodded as well.

"Yeah, I'll succeed."

I tried my best to answer assertively then turned my gaze to the sky.

Yggdrasil's branches were steadily removed. The way things were going, we should be able to approach within the distance before the branches started spreading—roughly fifteen kilometers away from it, but...

"But if Yggdrasil hopes to lure us over, it will very likely make another move before we attack the main body."

"In other words, we cannot even enter the showdown stage unless we counter its next move. Although Yggdrasil's plans are unknown yet, I will foil its ploy."

Lisa puffed out her magnificent chest and declared. Seeing her bosom wobbling, I scratched my face, embarrassed in various ways.

"Then I'm counting on you. It's about time we return."

"Very well."

Thus, we made our way to the van, but just as we were about to get on, I noticed the door was slightly ajar.

Huh... I thought I had closed it properly.

I checked the interior to see if anyone had gone out but the girls were all sleeping.

"Is something the matter?"

"Oh, no, nothing."

I shook my head at Lisa's question and entered the van.

The time had already passed 1am.

Dawn was still quite far away—

It was 4am when the situation changed.

Mitsuki and Firill were making their third sortie as Team 1 when...

"What—This is...!?"

Hearing Shinomiya-sensei's voice from the front passenger seat, I looked up.

Intending to rest, Lisa and Tia also widened their eyes.

'The branches' growth rate has suddenly sped up! We cannot keep up!'

'They are coming from the side in addition to the front!'

Through the communicator, I heard Mitsuki and Firill's voices.

"Continue the attack. Lower your altitude as a precaution. I will send reinforcements."

Shinomiya-sensei swiftly issued orders then looked back at us.

"Everyone wake up! Emergency situation. Yggdrasil has suddenly started to extend branches fiercely to expand its interference range. Team 2 and Team 3 go assist."

Hearing Shinomiya-sensei's voice, Ariella, Ren and Iris woke up. Apart from the driver, all of us got out after the van made an emergency stop.

The illumination from flares created through transmutation showed shadows of branches approaching with astounding speed.

Holding her laptop, Shinomiya-sensei looked at the screen and continued speaking:

"The electromagnetic wave anomaly zone is also expanding from the left and right sides, intending to surround us. Team 2, handle the right side. Team 3 will take care of the left."

"Affirmative!"

Hearing Shinomiya-sensei's orders, Lisa, Tia and Ariella enveloped themselves in wind and flew into the sky.

"Mm...... Mjolnir."

Rubbing her sleepy eyes, Ren summoned her hammer shaped fictional armament and followed the other girls.

Shinomiya-sensei turned her gaze to me and Iris who were left.

"You will standby until the situation becomes clear. If our advance becomes impeded, we may need to use your powers to open a path."

"...Got it."

I nodded. With a solemn expression, Iris voiced her opinion to Shinomiya-sensei.

"I think we should attack Yggdrasil's main body directly instead of running away! If it's my Catastrophe, surely the branches can be erased from the root."

"That would be great if it were possible, but this location is roughly thirty kilometers away from Yggdrasil, too far away to snipe the main body. The Catastrophe used by Basilisk had a maximum range of ten kilometers. Even if you could do the same, you won't be able to hit Yggdrasil from here."

Shinomiya-sensei calmly rejected Iris' proposal.

"No way... In that case, let's focus our attacks ahead of us to break through all at once—"

"I am reviewing that plan too... But the branches are growing abnormally fast. Even if we focus firepower ahead of us, we might end up surrounded by branches from the flanks before we get near to Yggdrasil."

Shinomiya-sensei stared at the computer screen while answering.

—Growing abnormally fast?

Hearing those words, I frowned.

"Right... Come to think of it, that's very strange. The Yggdrasil we fought at Midgard did not have this power of supernatural growth."

Speaking of which, the fact that Yggdrasil suddenly appeared in Japan was quite unusual to begin with. Yggdrasil's initial main body to appear took twenty years to grow up to 500 meters, yet this Yggdrasil was 5000 meters tall from the start.

The Yggdrasil showing up at Midgard could expand in size by stealing dark matter from the Ds, turning it into its physical body. It was definitely not growing by its own power.

"The current Yggdrasil... might have some kind of massive energy source."

I looked up at the sky and muttered. With the other girls deployed on the offensive, there were many more explosive flashes of light in the sky.

"Massive energy source?"

Iris looked at me with puzzled eyes.

"—I don't know what it is either. It's just that this situation can't be explained otherwise."

Since I did not know the answer, my reply became vague.

Hearing our conversation, Shinomiya-sensei immediately spoke up:

"Your deduction is intriguing. But if that's the case, one solution is for us to hold out until that energy source is depleted..."

Shinomiya-sensei murmured but after looking at the screen, she showed alarm on her face.

"Hmm—The electromagnetic wave anomaly zone has not stopped expanding. At this rate, communications will be obstructed and hinder monitoring of the interference range. All units return at once! Make a landing and focus on eliminating branches within visual range!"

Shinomiya-sensei anxiously issued orders.

Soon after, the girls descended from the sky with their fictional armaments.

Without given even a chance to catch their breaths, they started to attack the branches approaching from the sky.

"Slash, flare blade!"

Lisa swung her fictional armament, the spear Gungnir, and swept all the branches in front at once with a bright laser.

"Third Arrow—Lunar Eater!"

Mitsuki fired an arrow, pulverizing the branches on the right.

"Flare Burst Octet!"

Firill unleashed eight flaming projectiles, incinerating branches approaching from the left.

"Take this!"

Tia, Ariella and Ren continued to attack. Since the consecutive explosions served as illumination, everyone could focus on offense.

Everyone's attacks were very powerful. Every strike would eliminate a large number of Yggdrasil's branches but very quickly, new branches would arrive, blotting the sky.

"It's endless..."

Tia unleashed explosive flames at the sky and moaned in resignation.

"Although we are holding out, we won't be able to move at this rate."

"Mm."

Ariella showed an expression of hardship. Ren nodded in agreement.

"—I hope you will sustain the current situation a while longer. If the branches' growth rate show no signs of subsiding in fifteen minutes, we will retreat and regroup."

After some consideration, Shinomiya-sensei made the above decision.

She had decided on a fifteen minute waiting period before retreating possibly in consideration of the energy source I mentioned. Even if Yggdrasil was using some sort of power to grow, there should be a limit.

With bated breaths, Iris and I watched our friends in battle. Once the decision to withdraw was made, my anti-dragon armaments and Iris' Catastrophe would be used to cut open the path for retreat.

But if possible, I wanted to press the advance to settle things.

'Neun—Authority—Must have... Self-preservation... Antibody, counter, desired—'

I could already hear Yggdrasil's voice clearly in my mind.

For some reason, it pursued me, and quite desperately too—

It was almost like... It was afraid of something.

"Mononobe, are you okay?"

Iris asked me worriedly.

"...To be honest, not really. We're clearly outside Yggdrasil's interference range, but I keep hearing its voice. If we get in range of its interference, my consciousness might get invaded all at once."

I analyzed my condition and replied to Iris.

"Then we must find a way to get rid of those branches."

"Basically. Once we know what Yggdrasil is using as an energy source, we'll know how to counter..."

I looked up at Yggdrasil's branches that showed no signs of slowing down and prayed for them to have a limit.

But the branches showed no slowing in growth and regeneration. Fifteen minutes were about to end.

At this moment, a red beam of scorching heat swept across the sky from the east.

The air temperature increased all at once. As far as the eye could see, all branches were incinerated to ash.

"What!?"

Lisa exclaimed in surprise and everyone looked at the eastern sky.

A dot of light was approaching. Instantly, the dot became bigger and I noticed it was a girl enveloped in flames.

Dispelling the flames used for propulsion, the black-haired girl landed lightly. Kili Surtr Muspelheim. However, John, who was supposed to be working with her, was not in sight.

"Kili, why did you come?"

I asked and Kili replied in exasperation:

"I'm here to complain because you're ignoring my warning and acting recklessly. At this rate, you'll be overwhelmed. Hurry and retreat. A battle of attrition against the current Yggdrasil is futile."

"Futile... Why are you so sure?"

Unable to agree, I asked her in return.

With a gaze of pity, Kili looked at the western sky in Yggdrasil's direction.

Despite feeling concerned about Kili, Mitsuki and Lisa continued to attack the relentlessly approaching branches.

"I told you already, Hekatonkheir was created by Vritra—Mother—Do you still remember?"

"Y-Yeah."

I still nodded even though I felt troubled by Kili's sudden question.

"Due to forsaking me, Mother lost her relay with Hekatonkheir. What follows is only my speculation. Forced into a corner, Mother created a new Hekatonkheir in an attempt to eliminate her natural predator, Yggdrasil."

"You're talking about Hekatonkheir attacking Yggdrasil in a suicide bombing?"

I recalled the shocking news during the preparations for the school festival.

"Yes, but that operation ended in failure. Then I think Yggdrasil probably deduced Mother's hiding place based on the location where Hekatonkheir appeared."

"The location where Hekatonkheir appeared, don't tell me—"

I remembered that the resurrected Hekatonkheir had appeared in Japan. Although the detailed location escaped me, according to what Kili just said...

"Indeed, it is nearby."

Kili confirmed my imagination.

Hearing our conversation, Shinomiya-sensei said in surprise:

"So what you mean is: 'Black' Vritra... has been hiding in Aokigahara all along?"

"Most likely so. Although I knew Mother was in Japan, she did not tell me the precise location. In any case, it shouldn't be a hiding method as ordinary as lurking underground."

Kili nodded in confirmation while adding to her explanation. Indeed, if it was that kind of hiding method, let alone Yggdrasil, even humans would discover Vritra quickly.

"Mother is the dragon possessing the original power to generate dark matter whereas Yggdrasil has the ability to interfere with dark matter—Need I say more? Why Yggdrasil appeared here in such a gigantic state... Why a battle of attrition is useless—You should understand the reason now."

Kili looked at me as though testing me and asked.

Just as she said, I already guessed the answer.

"The energy source being used by Yggdrasil is... Vritra's dark matter, right?"

Just as it had stolen dark matter from Ds to grow at Midgard, the current Yggdrasil was also using Vritra's dark matter to enlarge itself.

"Correct. Yggdrasil has probably made Mother into its seedbed by now."

Kili confirmed my guess calmly.

"I see..."

Like last time, there was evidence proving the truth of Kili's words.

But the fifteen-minute time limit set by Shinomiya-sensei was about to pass and the branches were still growing with astounding speed. We were already out of options.

"Let's retreat, everyone."

I prepared myself and called to everyone.

"NO!!"

However, a voice of objection instantly ripped through the night's quiet atmosphere.

Tia stopped attacking and looked at me with eyes filled with determination.

"Yggdrasil must be defeated now! Tia will protect Yuu!"

"Protect me?"

"......"

Tia stared at me silently. Seeing her like that, I suddenly recalled—

"Don't tell me you overheard my conversation with Lisa—"

I remembered how I returned from the discussion with Lisa outside the van to find the door slightly ajar. Most likely, Tia had hid in the car's shadows to listen on our conversation.

Tia nodded in admission with tears overflowing from the corners of her eyes.

Scattered around the van, continuing to attack the branches, the rest of the girls looked at Tia, wanting to know what happened.

Crap—

It was too late for me to stop her.

"At this rate, Yuu's body will be taken over by Yggdrasil, right!?"

Tia's voice trembled, yelling out what I had kept a secret from everyone.

"—!?"

The ones who gasped after hearing those words were Mitsuki, Firill and Ariella. They paused in attacking.

Already privy to the secret, Iris, Lisa and Ren looked at me with worried eyes.

Shinomiya-sensei, who was not supposed to know, showed no signs of wavering. Perhaps the principal might have said something to her.

Despite showing surprise, Kili immediately switched to an expression of comprehension.

"Really? So you're being targeted by Yggdrasil too. No wonder... Fufu, now it's certain. As expected, I didn't make the wrong choice."

Seeing Kili smile happily for some reason, I felt a chill down my spine.

But that fear was swept away by the words I heard next.

"Nii-san... What is going on?"

The instant Mitsuki's voice shook my eardrums, my mind went blank.

I turned my head back in trepidation, only to see Mitsuki staring at me with a quivering gaze.

Chapter 4 - Ether Wind of Gold

Part 1

Tia Lightning thought back to what Kili Surtr Muspelheim had told her at the Castle of Mirrors.

"As things stand, Tia, Yggdrasil cannot be defeated no matter what. But if you give up your human identity, there might be a path to hope."

"Eh...?"

Tia stared blankly at Kili.

The hall all covered with mirrors gave an illusion of infinite space. At the same time, it also produced countless reflections of Tia and Kili.

An uncountable number of virtual images—Facing the black-haired girl was the girl with two red horns on her head in great unease.

"I originally planned to raise you as the trump card for taking down Yggdrasil. Your horns are also an organ existing for the sake of opposing Yggdrasil."

"These..."

Putting her hands on her head, Tia touched her two red horns.

"Indeed, this is an organ connected directly to the brain, which is why I can't put it on myself. Manipulating your own brain will mess up your concentration in the process, causing the control of biogenic transmutation to fail."

"Then... If Tia works hard, Yggdrasil can be defeated?"

Tia asked timidly but Kili shook her head.

"No, I haven't finished with your treatment, so those horns cannot function as intended yet. But if you wish, I could perform the final treatment for you."

Staring into Tia's eyes, Kili made this proposal.

"Then like this... Tia will be able to help Yuu and the others?"

"If all goes well. After all, I can't guarantee success since this is the first time, but if your horns function as planned, Yuu and the others have a shot at victory. However—"

Kili paused and narrowed her eyes.

"—The moment Yggdrasil is defeated, you will surely become a dragon transcending the boundaries of Ds and humans."

"...!"

Tia gasped and took a step back.

"Don't worry, I won't force you, so no need to be afraid. I'm no longer a puppet controlled by Mother. I will freely decide my 'way of living' according to my own will, so please make a choice according to your own wishes."

Kili's expression turned gentle and she smiled at Tia.

"Kili..."

It was a gentle smile that Tia had never seen on Kili's face.

"Yuu said before that how one lives their life is more important than what they are. What matters is not the identity of your existence, but what you want to do."

Part 2

In the middle of this predicament with Yggdrasil's branches flooding towards us, I was stunned on the spot with all eyes on me.

My secret had been revealed.

The fact that Yggdrasil was stealing my body had been exposed.

Finally, she still ended up finding out. Clearly when Mitsuki was the one person I did not want to know this secret.

"Mononobe-kun, tell me the details."

"I want to hear your explanation."

Firill and Ariella approached to question me.

"Yuu, tell Tia the truth..."

Tia stared at me with determination, refusing to back down by a single step.

"I'm interested in the details too."

Kili urged me to explain with her gaze.

By this point, I could not cover things up anymore.

Gritting my teeth, I searched for an answer to give them, but—

"Mononobe Yuu, clearly the only choice is to tell them. The weapons you used so far to defeat dragons were created based on data provided by Yggdrasil. The price you paid is that your body is now about to be stolen."

Lisa's fictional armament fired a flash of light, attacking the branches above while she spoke to me.

However, what she said felt strange to me.

"Huh...?"

Hearing her say that, Iris stared wide-eyed from the side.

The price paid under the deal with Yggdrasil was the loss of my memories, while taking over my body was the trap it had laid. These two were a bit different in meaning.

When my thoughts reached this point, I noticed something. When Tia overheard my conversation with Lisa, the subject of memory loss was not mentioned.

Then at least the worst situation—that I was not the "Mononobe Yuu" whom Mitsuki knew—Perhaps this one fact could still remain hidden to the very end.

...Thank you, Lisa.

While feeling grateful for Lisa's quick thinking, I started to explain to Mitsuki and the others.

"Just as Lisa said, I secretly made a deal with Yggdrasil to defeat dragons. But there was apparently something similar to a computer virus in the data that was sent, so gradually—and right now—I'm being invaded by Yggdrasil."

Omitting the memory part, I revealed the truth.

"To defeat dragons...? Could it be that three years ago, Nii-san, you—"

Mitsuki murmured blankly.

Three years ago, to protect my hometown, I used a power, which was normally impossible, to repel Hekatonkheir. This was done exactly by relying on anti-dragon armaments created from the weapons data obtained from Yggdrasil.

Smart as she was, Mitsuki seemed to recall that immediately.

"Yeah, the fight against Hekatonkheir three years ago was the first time."

I nodded in response to Mitsuki, despite knowing that Mitsuki would feel heavily guilty as soon as I confirmed it.

However, this was much better than telling her "the price was memories."

As long as Yggdrasil was neutralized, its invasion of me would presumably stop, but there was no guarantee my memories would recover.

When it was impossible to recover the real "Mononobe Yuu"—I did not want to bring despair to Mitsuki.

"Mononobe-kun... Why did you hide this? If the weapons for defeating dragons is the reason, then you must have made a deal again back when I was in a crisis, right?"

Firill glared at me angrily.

"...Sorry, because I didn't want you to feel responsible or in debt. Also, I only found out recently I was being controlled. I never expected things to turn out this way."

I bowed my head and apologized to Firill.

Seeing me like that, Ariella scolded:

"I understand how you feel, Mononobe-kun, but it pisses me off that we're the only ones kept in the dark. From the way it looks, Iris and Ren also knew in addition to Lisa, right?"

Iris looked down in shame when Ariella glanced at her, but Ren met her gaze and pointed her finger in the air.

"Mm."

I took a closer look. Because fewer people were attacking, the branches were gradually closing in.

"—Meaning it's not the time for arguing? Can't be helped, I'll complain properly later."

Ariella returned to attack after glaring at me.

"Me too... I have things to say but I'll hold back for now."

Firill turned her back to me and started attacking the branches again.

"—As thanks for letting me hear something interesting, I'll help out a bit."

With a wave of her hand, Kili incinerated branches with a red beam of scorching heat.

But in this situation, Mitsuki and Tia did not take their gazes off my face.

I saw Mitsuki biting her lower lip, shoulders trembling, a tear sliding down her cheek.

"M-Mitsuki—Don't cry. It's really my fault, I'm sorry—"

Even I was surprised at how shaken I was inside. I kept apologizing to her. To me who had lost all memories beyond three years ago, she should not be someone "special"... But my heart was shaken to a ridiculous degree.

"...Nii-san, you need not apologize. I am crying because I am too useless... This fills me with chagrin... So do not worry about me."

Mitsuki spoke hoarsely and brusquely wiped her tears away with her hand.

"Putting that aside, please allow me to confirm one fact. Is what you said just now everything?"

"Eh..."

My heart pounded like crazy.

"I knew long ago that you were hiding things from me, Nii-san, but I also understood you were hiding desperately... So I deliberately refrained from asking, but this incident has filled me with extreme regret. So this time, I will muster my courage to ask you, Nii-san, are you still hiding things from me?"

Mitsuki asked me with conviction.

I thought I had concealed things well, but now I knew I was totally seen through.

More than anyone else, Mitsuki knew this person of "Mononobe Yuu." She knew everything about me that my current self had forgotten. In front of someone like that, of course hiding would not work.

"...Yes."

I nodded to confirm Mitsuki's question, but I continued:

"But I can't tell you, Mitsuki."

I prepared myself and asserted clearly.

"Why?"

"I still can't say it yet."

I shook my head and stared into Mitsuki's eyes that were red from crying.

"Then when can you say it?"

"—Once I've retrieved everything."

I gave this answer because I could not think of another way of saying it.

"Even if I ask you what you mean by that, you will not answer, right?"

Mitsuki smiled wryly with feelings of resignation.

"...Sorry."

"Very well—Because I know how stubborn you are, Nii-san, I will not force the matter at this time. However, one final matter, please tell me—Tia-san said that Yggdrasil must be defeated now. Is that true?"

Mitsuki's expression tensed. She asked me in a tone of suppressed emotion:

"...It's true that Yggdrasil's interference in me has strengthened, but I won't get controlled by it immediately, so there's still time. We should retreat temporarily."

To be honest, I had a feeling that the final time limit was not far away, but I answered this way to reassure Mitsuki. Because right now, we were totally out of options.

I was admittedly happy that Tia said she would protect me, but right now, we should retreat and request reinforcements from Midgard. With a larger force, it might be possible to handle the branches' rate of growth.

"I understand. Indeed, as the captain of the Dragon Subjugation Squad, there is no alternative as a decision. Well then—"

Mitsuki paused halfway then turned to face Shinomiya-sensei.

"Shinomiya-sensei, forgive my willfulness, but I, Mononobe Mitsuki, hereby relinquish my duties as captain of the Dragon Subjugation Squad."

"What are you suddenly..."

Shinomiya-sensei was shocked.

The others, still attacking branches, also stared in Mitsuki in surprise.

"Mitsuki-chan...?"

Troubled, Iris called her name, tilting her head in puzzlement.

"Mitsuki..."

Tia also showed doubt on her face but I could also see her trying to figure things out.

But ignoring everyone's reactions, Mitsuki turned to face me.

"Starting now, I will only fight as your younger sister to protect you, Nii-san. I will absolutely not retreat."

"H-Hey—I said there's still time, right?"

"Nii-san, do you think lying can deceive me?"

As though having come to a realization, Mitsuki showed a refreshing smile while glaring at Yggdrasil's branches extending from the western sky.

"Hold on, what do you think can still be done in this situation? If there's a solution, I wouldn't call for a retreat."

The way I saw it, Mitsuki was going to attack recklessly without a plan. I made haste to stop her.

"Indeed, given the current situation, marching forward while keeping sufficient distance from the interference range will be impossible. However, much can be done as long as one disregards one's safety. Such notions would disqualify a commander... But right now, I am merely a younger sister, nothing more."

Mitsuki smiled as though telling a joke and continued:

"By eliminating branches in the minimum range ahead and flying at high speed, it might be possible to advance."

"What...? But if you get caught in Yggdrasil's interference range, even if just a little, you'll crash immediately, right? It's too dangerous!"

I instantly yelled in objection.

"—I know, which is why I intend to go alone. I will find a way to reach a spot where I can aim at Yggdrasil directly, to destroy the base of the branches. That way, I should be able to buy quite a lot of time before it grows again. Nii-san, you and the others will use that window to attack."

Mitsuki's expression showed that she was completely prepared already.

"Don't do something stupid like that—"

I reached out, trying to stop Mitsuki, but she was surrounded by a layer of wind, deflecting my hand.

Everyone tried to call out and stop her with frantic expressions.

But before anyone could make a sound, she acted even faster.

"Wait!"

Mitsuki hovered into the air, but Tia crashed into her, wrapped in her own layer of wind.

"Kyah!?"

Entangled together, the two girls fell to the ground.

"Tia-san, let go of me!"

Mitsuki tried to pull off Tia who was hugging her waist but Tia resisted desperately and yelled:

"Don't do that, Mitsuki! Leave it to Tia! If it's Tia, it will definitely succeed!"

"Huh...?"

Hearing what Tia said, Mitsuki stopped.

"Sorry, Tia should have said this earlier, but Tia finds the current life so happy... Don't want any change... So Tia could not gather enough courage. But Tia has decided now."

Tia separated from Mitsuki who had stopped resisting, then looked at Kili.

Originally helping out with eliminating branches, Kili stopped and faced Tia at this time.

"Is that right? Tia, you will be choosing your way of living."

Kili spoke gently to Tia.

I did not know what was going on, but my heart was in turmoil.

Tia nodded and said with a voice of determination:

"Please, Kili, give Tia the power to fight Yggdrasil."

"Got it, then I'll perform the final treatment for you."

Kili slowly approached Tia.

"Hey, what treatment? What are you planning to do!?"

Unable to grasp the situation, I yelled acutely at Kili.

"—I will make Tia's horns complete."

Kili placed her palm on the pair of horns on Tia's head and gave me a brief answer.

"Make her horns complete... What on earth is—"

"Tia is the child I raised to become the trump card against Yggdrasil. These horns were created as an organ for opposing Yggdrasil. Although the horns currently don't function, so long as Tia wishes, I can make these horns complete. This was what I proposed to her at the amusement park."

Staring at Tia's horns, Kili quietly explained.

So that was what they talked about in the Castle of Mirrors that time—

"...Tia has been brooding the whole time after returning from the amusement park, like she was in a dilemma... afraid of something. Is that final treatment something frightening to Tia?"

I stared at Kili and questioned her in a fierce tone of voice.

"Yes, I don't know what will happen if it fails. Even if it succeeds, Tia will become an existence transcending the boundaries of what it means to be a D. Based on Midgard's definitions, she might end up categorized as a dragon."

Hearing Kili's words, Iris' shoulders shuddered.

As a D who had transcended boundaries, Iris must have felt greatly shaken inside after listening to Kili.

"I won't let Tia do something so dangerous!"

"That's not for you to decide."

Just as I tried to take a step forward, a small explosion detonated in front of me.

"!?"

I guarded my face with my hand and jumped back reflexively. The searing pain on my skin forced me to frown.

"Don't get in the way, Yuu. Even you have no right to stop Tia from choosing her own path."

Exuding off intense killing intent, Kili restrained me from taking action.

The surrounding temperature rose. Sweat was seeping out of my forehead and neck. She must have deployed Muspelheim.

What should I do...? Stopping them would require the determination to murder Kili.

Just as I hesitated, Tia smiled at me.

"Don't worry. Because no matter what Tia becomes, Tia will be still the one who loves Yuu most—Yuu's wife."

Then the dark matter generated in Kili's hand melded with Tia's horns as though getting sucked in.

"—!!"

The two horns shone with dazzling light while Tia emitted a deafening scream.

Part 3

Blinding light and an extended scream.

"Tia!"

Ignoring Kili's deployed Muspelheim, I dashed towards Tia.

The final treatment probably ended in an instant—Kili did not stop me. After she put down her raised hand, Tia immediately collapsed on her knees.

As though sliding, I caught Tia's petite body, feeble and drained of strength.

"Stay with me! Tia!"

I called to her but Tia seemed to have lost consciousness. No reaction. Her two red horns also showed no change in appearance.

"Tia-chan, are you okay!?"

"Tia-san!"

Iris and Mitsuki rushed forward from behind, peering at Tia's face.

Unable to leave their positions from eliminating branches, Lisa and the others looked in our direction with paled faces.

I looked up and glared at Kili.

"What happened to Tia? Did it—fail?"

"Can't tell until Tia wakes up. The completed horns have connected to Tia's brain, so as long as she is able to withstand the strain, she'll surely—"

Just as Kili spoke in a praying tone of voice, Tia stirred.

"Mm..."

A faint sound came Tia's pink lips. A spark of lightning flashed and popped near her red horns.

"Tia can hear..."

Tia spoke hoarsely while opening her eyes slightly.

"Thank goodness, you woke up."

I breathed a sigh of relief, only to see Tia staring at me.

"Tia can hear a cold voice calling Neun... Neun... Is this the voice of Yggdrasil that's troubling Yuu?"

"What...? You can hear it too, Tia?"

I asked in surprise.

Just as Tia said, Yggdrasil's voice was still sounding in my mind right now.

"Yes... So this is Yggdrasil... Yuu's enemy."

Tia spoke as though in the middle of a dream and stood up.

"Tia?"

I noticed Tia acting a bit strange and called to her but she focused her gaze westward towards Yggdrasil instead of answering. The electrical sparks scattering over Tia's head in the horns' surroundings gradually increased.

"...Stop making Yuu suffer, be quiet!!"

The instant Tia yelled, electricity exploded nearby.

"What!?"

Boom, Shinomiya-sensei's laptop exploded. The surroundings suddenly felt quiet.

"Yggdrasil's voice... disappeared?"

I muttered blankly. Yggdrasil's voice was originally loud enough to feel noisy, but now, no matter how I much I focused my mind in order to listen, I could not sense the voice anymore. The sense of dissonance in my left arm also disappeared.

"Looks like it succeeded."

While everyone was feeling troubled, Kili was the only one to show a contented look.

"What did Tia do?"

I demanded an explanation from Kili.

"—What Tia has constructed is an electromagnetic barrier that could probably block out Yggdrasil's interference completely. And if my predictions are correct, Yggdrasil is currently unable to steal Tia's dark matter. Just by maintaining this barrier, your side will be able to enter Yggdrasil's interference range."

"What... Tia is now capable of that kind of thing?"

I gasped and asked.

"Yes. Speaking of which, the reason why Yggdrasil can steal dark matter is because electrical signals simulating thoughts will have more interference strength than weak mental waves. That's why I've given Tia a renewed organ capable of outputting thoughts as electrical signals."

"Namely... those horns?"

I looked at Tia's horns, surrounded by glowing electricity.

"Also, Tia has a habit of subconsciously transmuting dark matter into electrical currents. When the dark matter is transmuted emotionally, it becomes equivalent to thoughts encoded into electrical signals. This further strengthens Tia's interference strength, repelling Yggdrasil's interference. This is the truth behind the electromagnetic barrier."

Thinking back, Tia really did have a habit of generating electrical currents when emotional. That was probably why Kili had chosen Tia.

After listening to that, Tia held her head and asked Kili:

"So... If it's Tia right now, Tia can protect Yuu and the others?"

"That's right. As long as you think intensely and generate dark matter persistently, the electromagnetic barrier will be sustained. As long as they stay inside the barrier, the dark matter of Yuu and the others will be free from interference."

"Got it... Tia will work hard."

Tia nodded and moved her hand away from her head. I saw pearl-like sweat on her head.

It was probably causing her quite a lot of strain. Bestowed with an organ that was not inborn, it was only natural for her body to have a rejection reaction.

But Tia steadied her shaking body with her legs and spread the pair of red wings that was her fictional armament.

"Yuu—Everyone follow Tia. Tia will take everyone to Yggdrasil."

Tia spoke with unshakable determination.

Will you be okay? I could only swallow these words.

Because I quickly understood that it was a meaningless question. Asking it would be a waste of time.

I could see that she was not okay at all. She was clearly forcing herself.

In reaction to becoming like this—No, she had chosen to do this.

Simply for the sake of protecting me.

Lisa silently approached Tia and hugged her.

"—I know, then I will count on you, Tia-san. However, please focus on maintaining the barrier. I will fly and carry you."

"Thank you... Lisa."

Tia dispelled her fictional armament and held onto Lisa's waist.

"...I will carry Onii-chan."

Feeling someone pull my right hand, I turned my gaze to see Ren looking up at me.

Ren's cooperation with me was the key to the next part of the plan, so it was probably better that I traveled with her.

"Okay, I'm counting on you."

I held Ren's hand. Having confirmed the situation, Mitsuki walked over to Iris and took her hand.

"Then I will be responsible for Iris-san's transport. So this is it—Shinomiya-sensei, we are setting off."

Holding the wrecked laptop in her hand, Shinomiya-sensei was looking a bit lost. Then at this time, she smiled wryly and acknowledged.

"Okay... Looks like I can't provide support anymore, so I'm leaving the rest to you. Captain of the Dragon Subjugation Squad—Mononobe Mitsuki."

Shinomiya-sensei intentionally added the title when addressing Mitsuki.

Having just declared she would relinquish her duties, Mitsuki made a slightly embarrassed look before saluting with upright posture.

"Affirmative. I will fulfill my duties as the captain of the Dragon Subjugation Squad."

Part 4

Gathered around Lisa, who was carrying Tia in her arms, we flew through the night sky.

Yggdrasil's branches were growing at a frightening rate in front of us.

Although it was impossible to measure the exact interference range, the area under the branches was most likely its territory.

We cautiously lowered our altitude and rushed into Yggdrasil's interference range.

—No change.

Having confirmed there was no interference in our fictional armaments or any signs of impedance to transmutation, we increased our altitude and flying speed. The sky glowed white faintly. Dawn seemed to be approaching.

Flying in the lead while carrying Iris in her arms was Mitsuki. Holding the rear was Ren, transporting me, with Kili flying by our side.

"How unexpected. I can't believe you came along, Kili."

Flying in the sky with Ren holding my hand, I spoke to Kili beside me.

"Let me enjoy the show to the very end since I'm already here. Of course, I won't just watch. I'll offer a helping hand and won't drag you down, so relax."

"I don't doubt your abilities, but I'll be watching you to see if you have any ulterior motives."

I declared to Kili that I refused to trust her.

"Fufu, I don't mind. That means you'll have your eyes focused on me."

Kili smiled confidently.

"...!"

Her smile was inexplicably dazzling and stunning, rendering me speechless for a moment. Sure enough, this girl was not easy to deal with.

"However, you should probably focus your attention on Yggdrasil rather than me. Once it realizes its interference over dark matter isn't working, it will surely take other measures."

Just as Kili reminded me to pay attention, Mitsuki yelled from the front:

"Heads up, Yggdrasil's branches are showing changes! Be careful, everyone!"

I hastily looked up to notice that we were already under a canopy made from Yggdrasil's branches.

These capillary-like branches blotted the sky, writhing in a sinister and spooky manner. Numerous branches, as sharp as spears, were attacking our position.

"All units deploy shields! We will break through by force!"

Mitsuki commanded in a sharp voice.

"Looks like it's my turn."

Kili grinned proudly and raised one hand to the sky.

"—Such flammable-looking branches won't even manage to enter my Muspelheim."

The approaching branches suddenly caught fire, burning into tiny particles of ash.

She had most likely deployed an invisible barrier of high temperature in the air.

Mitsuki and the girls also deployed barriers of wind, but all the branches were burnt to ash before reaching them.

Under the gradually brightening sky, the outlines of Mount Fuji's tall appearance and the towering Yggdrasil were gradually coming into view.

"Target confirmed! Once we pass over Mount Fuji, our distance to the target will be 10 kilometers or so—Sniping distance. Iris-san, show time for you!"

"Yeah!"

Iris nodded in response to Mitsuki.

"Once we pass Mount Fuji, Lisa-san, Iris-san and I shall attack the main body in full force while trying to get even closer. Firill-san and Ariella-san, continue to deploy shields. Nii-san and Ren-san will prepare to scatter Ether Wind after the main body is destroyed!"

"Yes!"

I answered and made eye contact with Ren, exchanging nods in acknowledgement.

"Huh? What about me?"

Without being called on, Kili asked, prompting Mitsuki to reply in a cold voice:

"If you wish to help, please participate in attacking."

"Oh dear, it feels like you're not expecting much of me?"

Kili grumbled with dissatisfaction.

Immediately, Iris, who was carried by Mitsuki, looked back and smiled cheerfully at Kili.

"It's not like that, Kili-chan, let's do our best together!"

"...Y-You're really good at getting others caught in your pace. Fine, whatever. Having created this chance for Tia, even without being told, I seriously intend to go on a rampage."

Kili spoke with violence in her eyes.

The snowtop of Mount Fuji was before us, but the branches suddenly stopped attacking.

Just as it seemed like Yggdrasil had given up on obstructing us with branches, Lisa yelled acutely.

"Look quickly! Yggdrasil's shape—"

Located on the far side, Yggdrasil's towering trunk was gradually expanding unnaturally in the middle.

Then bizarre and thick branches were forced out from the bulging portion.

The sun seemed to rise at last and the sky brightened all at once. Behind us, the sun's rays from the east were making us slightly dizzy.

"Everyone! Go down rapidly right now!"

Just at this moment, I heard Tia shout anxiously.

"Yggdrasil's target is Tia!"

Hearing Tia's urgent voice, everyone lowered their flying altitude without fully understanding what was going on.

In the next instant, a flash of blinding light rushed past us above.

"W-What was that!?"

Firill cried out in surprise.

"No idea, it seems like something flew out from Yggdrasil..."

Ariella had not figured out the situation either.

"Dodge quickly! It's aiming again!"

Tia yelled again.

"Descend further!"

Mitsuki instantly ordered us.

After we obeyed, another flash of light passed over us.

"That light... Its speed... The power of electrical interference—It might be an object shot at high-speed using electromagnetic induction."

Flying ahead, Mitsuki said in a stiff tone of voice.

"Isn't that a railgun!? Isn't it impossible to dodge if something like that is aiming at us!?"

Lisa yelled anxiously but Kili interjected confident after hearing her:

"—Don't worry. Tia noticed the attacks in advance, twice already, right? Tia, did you feel anything?"

Tia nodded lightly at Kili's question.

"Yes, there's a dangerous feeling."

"I knew it. Tia's horns are also quite sensitive towards external electromagnetic waves. Although it wasn't an ability by deliberate design, as long as we have Tia, we should be able to dodge."

After Kili said that, Tia made an alarmed expression and yelled:

"It's coming again!"

"All units dodge right!"

Mitsuki instantly commanded.

I could see a glowing ball shot out from the branches protruding from Yggdrasil's trunk.

Just as I was thinking that, a blinding light flashed past our left.

As Lisa said, it would be impossible to dodge visually.

But such a powerful attack could very well get me caught up in it too. Yggdrasil seemed quite shaken when harming me in Midgard. Although the reason was unknown, it looked like it wanted to obtain me intact.

Nevertheless, Yggdrasil seemed to be prioritizing the elimination of Tia over ensuring my safety. Perhaps that was how much of a threat it viewed Tia.

"It's not over!"

We listened to Tia's directions and steadily closed in on Yggdrasil while evading the railgun shots.

Finally, we passed over Mount Fuji's peak.

The railgun shots we dodged dug up the side of Mount Fuji. Amidst the cloud of dust and debris, Mitsuki issued orders.

"Begin the attack on Yggdrasil's main body! If the main body is like a CPU, damaging it ought to lower Yggdrasil's computation power. This might be able to dampen its unrestricted growth and regeneration."

"Understood!"

In charge of attacking, Iris and Lisa responded.

Kili also went "got it" and went up to the front with a fearless smile.

Mitsuki raised Brionac. Holding onto Mitsuki's waist with her right arm, Iris raised her left hand.

"Come, come, fragments of time—"

Iris murmured like praying then generated a red glow in her hand immediately. The words she uttered served as an incantation to focus her mind. She had apparently made changes in order to use Catastrophe.

"—Caduceus Catastrophe!"

With a shout, the red glow turned into the shape of a staff. At first glance, it seemed to be a fictional armament of a different color, but most likely, no dark matter had been used.

It was definitely what Iris had used at Midgard last time, a staff formed from concentrating the light of Catastrophe.

"Iris-san, please attack after me!"

While Iris was preparing, Mitsuki aimed at Yggdrasil and fired the first shot.

"Terminating Arrow—Last Quark!"

Mitsuki fired an antimatter arrow that had eliminated several dragons to date.

But as though to block the arrow's advance, the branches spread above came down, entangling one another, forming a wall.

Mitsuki's arrow caused a giant explosion upon contact with that wall, destroying the branches. However, due to the distance, the antimatter explosion did not reach Yggdrasil's main body.

The branches forming the canopy came down to attack us from overhead. However, they were deflected by Firill and Ariella's barriers. But during this time, branches formed a new wall in front of Yggdrasil.

"Our attacks won't be able to reach the main body if it bolsters its defenses like this!"

Lisa raised Gungnir and shouted.

"Don't worry, Lisa-chan, I'll eliminate them all!"

Pointing the tip of her red staff towards Yggdrasil, Iris shouted acutely:

"Catastrophe, actualize!"

The red light of Catastrophe pierced the dawn sky.

An attack of red light, rivaling Basilisk's, devoured the wall of branches that Yggdrasil had weaved, instantly weathering it away into dust.

Without weakening, the light struck the railgun's discharge port directly.

The longer the duration of exposure, the more time was stolen. Slicing through Yggdrasil's gigantic tree trunk, Iris' beam pierced straight through.

The original location of the discharge port was turned into a giant hole.

"Pierce, flare!"

Seizing the chance, Lisa fired her specialty, the positron cannon, from the tip of her spear. Her attack made a direct hit on the top part of Yggdrasil—the base of the branches.

Severed from the main body, the branches instantly stopped moving and started to fall gradually towards the ground.

Passing through gaps in the falling branches, we increased our altitude and got within Yggdrasil's vicinity. In front of our eyes was a towering gigantic tree that was way too enormous.

"My turn."

Completely fearless, Kili raised her right hand towards the sky.

"—Laevateinn."

Extending a scarlet flash of light towards the sky, Kili swung that flash down like a sword.

The sword of flashing light left a trail on the morning clouds in the sky.

Chopping Yggdrasil's main body vertically, the light sliced into the center of the tree trunk, causing a large explosion. That shockwave caused Yggdrasil's trunk to split apart left and right.

"This time, I will strike the target."

Aiming at the crack in Yggdrasil caused by Kili's attack, Mitsuki released another antimatter arrow.

The pure white light of annihilation erupted from the inside of the trunk. The internally detonated explosion caused Yggdrasil's body to expand greatly. Losing balance, the body gradually collapsed under its own weight.

"It is almost time. Descend to the ground, scatter Ether Wind and attack Yggdrasil's mind using the anti-dragon armament."

Seeing Yggdrasil collapsing, Mitsuki gave orders.

Ren would no longer be able to fly once she passed all her dark matter to me. Furthermore, the anti-dragon armaments had to be secured on the ground for support, which necessitated landing.

"Onii-chan...!"

"Yes, let's start."

Ren held my hand tightly and I gripped back in return.

Unless I followed up on the attack, all we had accomplished was merely destroying Yggdrasil's body. Sooner or later, it would transfer its core to somewhere else.

Hence, before that could happen, we must drag on the contents to destroy it after obliterating the main body.

Finding a location with good visibility, we landed at a lakeside near Yggdrasil.

Everyone scattered to protect Ren and me. Helped by Tia who was in charge of preventing Yggdrasil's interference, I generated dark matter.

"Fictional armament—Siegfried."

I created the fictional armament shaped like an ornamental gun.

Then Ren placed her hand on Siegfried.

"I will only think about you, Onii-chan, and you will only think about me. That way, I'll definitely be able to give all of it to you."

"—Got it."

While I nodded in response, Ren's dark matter poured in.

It was a massive amount that I had never succeeded in controlling before.

However, my fictional armament expanded in volume in a stable manner without its shape going into disarray.

By thinking of each other strongly, we caused our dark matter to merge without problems.

It felt like Ren's mind was naturally permeating into mine.

My fictional armament grew to several dozens of meters in size within the blink of an eye.

Ordinary matter of that size would be almost impossible to balance or support. But the dark matter forming fictional armaments had the property of responding to thoughts and had no weight.

Consequently, I could support it with no effort, simply by thinking silently in my mind, the enlarged Siegfried remained in midair. Thanks to the electromagnetic barrier Tia deployed for us, the dark matter would not get stolen.

Responding to my will, Siegfried pointed its muzzle towards Yggdrasil.

While aiming, I compressed the dark matter pouring in from Ren inside the fictional armament.

"Onii-chan, just a bit more."

"...Got it."

I focused my mind, not letting the fictional armament collapse.

The fictional armament showed a hint of red color. Perhaps this was the color of Ren's thoughts.

"—This is everything."

Then Ren's dark matter was all poured into my fictional armament.

I turned all that dark matter into a single bullet.

Transmuted into golden particles that caused souls to materialize—

"Ether Bullet!!"

The fictional armament vanished the moment the bullet was shot.

The golden bullet, with everything of Ren's and mine poured in, shot high into the sky. Giving off intense brightness, it then exploded.

Instantly, the sky's color turned from pale blue to a dazzling golden.

Glittering brightly, the radiant particles drifted down from the sky.

It was finer than snow—Like golden diamond dust.

Descending from the sky, the Ether Wind gradually covered Yggdrasil's collapsing main body.

"How is it...?"

I observed the situation with bated breath.

If Director Miyazawa's predictions were true, then Yggdrasil's mind ought to manifest.

Amidst the drifting brightness, an outline gradually surfaced.

A scene just as hoped, but—

"This is... impossible."

Ariella muttered blankly.

The others gasped in surprise.

I did not make a sound, simply shocked by the sight before my eyes—

Yggdrasil's soul was gradually materializing as though flooding out of its collapsed body.

It was an outline of a giant tree, whose branches extended to the other side of the horizon, completely blotting the sky.

Its size was not merely 5000 meters, but much more gigantic.

Seeing its outline cut off unnaturally, I could tell that what the Ether Wind caused to manifest was merely a small portion of the whole.

This gigantic soul, how do we destroy it?

Only then did I realize we were too naive.

Yggdrasil's true nature was a network built from all the plants in the world. On further thought, it would not be strange even if its soul was on the scale of the Earth.

Just as all members of Brynhildr Class were stunned. Kili quietly looked up at Yggdrasil and turned towards me.

"Yuu? Aren't you going to fight? You're destroying that thing, right?"

"—!"

Her words prompted me to regain my senses.

Indeed... By this point, there was no choice but to do it. This was surely Yggdrasil's core without a doubt.

No matter how despaired, for the sake of everyone who had brought me here, I must not give up!

"—Ren, I'm going to borrow dark matter from you again, to construct an anti-dragon armament this time."

"Mm!"

Ren's eyes blazed with fighting spirit. She gripped my right hand firmly.

"Anti-dragon armament Marduk—Psionic multi-barreled cannon, Noah!"

I transmuted the dark matter flowing from Ren into a pre-civilization weapon.

Performing transmutation using blueprints in the mind was much easier than making a fictional armament.

A double-barreled turret appeared on a rotating artillery platform. With a design of glowing lines carved on its surface, the multi-barreled cannon was linked to my consciousness, aimed at Yggdrasil.

As a weapon that amplified and shot out the gunner's thoughts, Noah was effective against spirit bodies which did not interact with ordinary matter. This was already proven during the battle against Hraesvelgr.

—I will defeat you. I won't become your possession!

"Fire!"

Turning strong willpower into energy, Noah's multi-barreled turret fired two shells.

The shells struck the materialized spirit body, causing golden particles to fly into the air.

However, Yggdrasil's spirit body was far too humongous. These tiny shells did not produce much trace of destruction.

"—Fire! Fire! Fire!"

Even so, I still fired relentlessly.

But the more I repeated, the more I realized that my attacks were equivalent to a toy gun against Yggdrasil's spirit body whose size was extraordinary.

Even if I were to shoot dozens, thousands of times, I did not think I would succeed in destroying it.

My consciousness gradually grew hazy because the more I shot, the more mental energy was consumed. Even if I increased the number of turrets like during the battle against Hraesvelgr, it was pointless because my mind's energy was limited as the source.

"Fire—Huff, huff, huff..."

After who knew how many shots had been fired, I breathed heavily. My vision was blurred from the sweat entering my eyes. I could see Yggdrasil's spirit body standing upright, completely unshaken.

"Damn... it..."

There was no time left.

The Ether Wind scattered earlier was fading bit by bit.

"Onii-chan..."

Ren looked up at me with worry.

"I'm fine... I can still shoot."

I feigned vitality and forced myself to answer, then glared at Yggdrasil's spirit body that had appeared due to the golden particles.

I must endure... As the only one capable of attacking spirit bodies, I could not rely on the others.

I had relied so much on them beforehand, so I must accomplish this—

But my knees gave way.

My body was about to fall over forwards.

I slowly approached the ground... But stopped just before my face smashed the ground.

"Huh...?"

I came to my senses only to find Mitsuki, Iris and Tia's face before me.

"Nii-san, are you okay!?"

"Mononobe!"

"Yuu!"

The three voices sustained my consciousness that was about to be cut off.

"—Thank you all."

I thanked them and got up, but this time, I fell backwards.

However, warm hands caught me this time too.

"Goodness gracious, get a grip on yourself and stand properly."

"Do your best, Mononobe-kun."

"Mononobe-kun, hang in there."

Lisa, Firill and Ariella supported my body from behind.

"Sorry. Thanks."

I thanked them. Standing in the distance all alone, Kili asked me:

"Yuu, are you at your limit?"

"No... Not yet. I feel power surging from within."

This was not pretense. I really did feel I could continue to fight fiercely.

My heart felt very warm and it seemed like the mental energy I had depleted had recovered a little.

However, this was surely just my own wishful thinking.

Thoughts or mental energy could not be transferred to others like dark matter.

—When this thought crossed my mind, a question occurred to me.

Really... Is that true?

Who decided that mental energy could not be transmitted? When was it proven?

Through training with Ren, I found out that dark matter from other people consisted of fragments of the mind—fragments of thoughts and feelings.

The transfer of dark matter was equivalent to sending your thoughts to someone. To sustain the psionic multi-barreled cannon, Ren's dark matter continued to flow.

Was dark matter really the only thing Ren was giving me?

Those hands, tightly held together, supporting my heart, perhaps that kind of power would—

"Everyone, can I ask you for a favor?"

I asked the girls.

"What is it? I am willing to do anything in my power for you, Nii-san!"

Mitsuki instantly answered and the others urged me to tell them.

"I hope you will transmit your thoughts to me using the same principles as dark matter transfer."

I did not know if this would actually pass mental energy over. Even if it could, it would probably serve as merely psychological consolation.

But in order to fight to the very end, I sought everyone's power.

"Thoughts...?"

Iris widened her eyes, cocking her head in puzzlement.

"Yes, lend me your thoughts... the power of your heart and soul."

"—I understand. Just thoughts and feelings, isn't that right?"

Lisa nodded, applying force through her hand that was supporting my back.

"Mononobe-kun... I will think of you as strongly as I can."

Gripping my shoulder firmly, Firill spoke.

"I will cheer for you, Mononobe-kun."

Ariella said while touching my back.

My heart began to warm up. Everyone's thoughts were making me happy. My mind gradually felt satisfied.

Was this mental energy flowing in? Or simply the effect of receiving encouragement? I did not know actually.

But my originally sapped strength surged again, this was the truth.

I slowly took the power received from everyone and poured it into Noah. The lines carved all over the multi-barreled cannon began to glow with dazzling light.

"Tia is always always thinking of Yuu!"

"Nii-san, please accept my thoughts!"

Tia and Mitsuki pressed their hands on my chest, praying strongly.

Then Iris placed her hands on top of theirs.

"Mononobe—"

Iris simply called my name and smiled faintly.

But I could feel it. I could feel Iris' thoughts. I could feel intense feelings that made my chest hot.

Not only Iris but Tia and Mitsuki's emotions and words were giving me power.

The multi-barreled cannon, which converted mental energy into shells, rumbled, giving off light that shone all around.

"Onii-chan...... Don't lose!"

Gripping my right hand tightly, Ren cried out as hard as she could.

Ren's thought flowed into me together with her dark matter.

I could feel the unprecedented power of thoughts, dense and fierce, gradually growing stronger inside the anti-dragon armament.

Everything was poured into this one attack.

Let me fire the thoughts and feelings of insignificant humans towards Yggdrasil.

Let it know that we are living with such fiery emotions in our hearts.

"We're doing it, everyone."

"Yes!"

The girls responded to my call.

Then in unison, we fired our thoughts.

"FIRE!"

An intense glow expanded from the two muzzles, shooting at the sky. While firing, the psionic multi-barreled cannon exploded from within and collapsed.

The two balls of light melded together, forming a gigantic shell, striking Yggdrasil's spirit body.

Immediately exploding with blinding light, golden particles then scattered all over the sky.

The atmosphere shook slightly. The outline of Yggdrasil composed of Ether Wind shook for an instant.

Once the particles scattered and disappeared in the air, I could see a massive hole opened up in the center of Yggdrasil's spirit body.

However, the spirit body showed no signs of overall collapse.

"Damn it! This didn't work either..."

I said with frustration.

"Onii-chan... One more time."

Ren pulled my hand. She did not show any signs of giving up in her expression.

"—Yeah, until it's destroyed, we'll shoot no matter how many times it takes."

I nodded and prepared to construct the anti-dragon armament again, but Kili stopped me.

"No, this is good enough."

Kili approached me and smiled with satisfaction.

"Enough...? Yggdrasil's core consciousness isn't destroyed though."

"But damage has been inflicted, so next is your job—Tia."

Kili patted Tia, who had been lending me power, on the shoulder and said to her.

"Tia's job?"

Tia widened her eyes and stared at Kili.

"You should be able to hear it, right? Yggdrasil's screaming."

"...Yeah, but it's a mess. Can't hear what it's saying."

"That is evidence that the core's functionality is damaged. Given now, Tia, you'll surely prevail over Yggdrasil."

Kili grinned and continued.

"Your pair of horns is not simply for defending against Yggdrasil's interference. It is a weapon existing for the sake of devouring Yggdrasil, a power to enable you to become a dragon."

"The horns are a weapon... Become a dragon—"

Tia touched the horns on her head, apparently thinking of something.

"Against Yggdrasil that's trying to take Yuu's place, just do the same thing to it. Tia, you have that power."

"—Yeah!"

Tia nodded. Looking like she understood what she must do, she constructed her wing-shaped fictional armament on her back.

"Hey Tia!"

Before I could stop her, Tia had already flown into the sky, heading for Yggdrasil.

"Kili, what are you planning to have Tia do!?"

I glared at Kili and asked her what was going on.

"I simply presented a choice. Everything is Tia's own decision. Don't belittle her resolve."

Glared back by her with such intense emotions, I could not help but gasp.

"Mind your own business and quietly watch Tia's battle."

Kili spoke in a sharp tone of voice to stop Lisa and the others from chasing after Tia.

"You will soon know what Tia is about to do."

Staring at Tia in flight, Kili spoke quietly.

Tia arrived at Yggdrasil's spirit body then jumped into the hole I had punctured.

Several seconds later, blindingly bright lightning erupted with Yggdrasil as the center.

Part 5

Flying through the air where golden particles drifted, Tia Lightning recalled the first time she met him—the time when she encountered Mononobe Yuu.

Back then, Tia did not quite understand much about herself.

Her parents called her human but demanded her to create gemstones through transmutation.

Later on, Tia and her parents were captured by an armed gang. This time, she was exploited as a D with the power to generate dark matter.

Hence, Tia had asked him—Mononobe Yuu who had rescued her from that armed gang—What am I?

Then with broken speech, he replied in Tia's mother tongue:

'You are a—cute, girl.'

It was a very gentle answer.

Tia wanted to become like that, hoped for herself to become like that, it was the answer Tia desired too.

Tia had always kept those words in her heart.

Meeting Kili, raised to become a dragon, selected by Basilisk—Tia had abandoned that dream once... But after reuniting with him and rescued by Lisa and the others, Tia made a decision as a result.

Tia would live together with Lisa and the others as humans.

To become the cutest girl of all in Mononobe Yuu's eyes—to become his wife.

Then like how he had protected her, she would protect him too.

"Tia will save Yuu!"

Tia generated wind from her fictional armament, a pair of red dragon wings, and charged into the interior of Yggdrasil's spirit body.

Her surroundings were covered by golden particles, so bright that her eyes could almost see nothing. Tia heard Yggdrasil's cries in her mind.

'Thought, flaw—collapse, reject—reject, reject, reject, repair, prioritize—'

Not just a voice. Through her horns, Tia could sense intangible feelings.

"—It's afraid."

Tia murmured.

Yggdrasil was afraid. Afraid of its consciousness disappearing, afraid of losing its existence, afraid of death—Extremely extremely frightened.

'Neun—needed, must have—uncertain, ninth authority, one and only—most suitable, survival strategy—'

And it wanted—

To survive, it needed Mononobe Yuu.

Tia could sense this concretely.

Tia did not know what it was afraid of. Yggdrasil's thoughts were fragmented, incomprehensible.

However—

"You're not having him!"

Tia declared to Yggdrasil in no uncertain terms.

"Because Yuu will become Tia's husband!!"

Tia poured all her thoughts into dark matter, transmuting it into electricity then released it.

Tia's consciousness spread as an electromagnetic field, expanding inside of Yggdrasil.

Attacked and damaged by Noah, Yggdrasil's core system had encountered a bug, allowing Tia's consciousness to invade.

Hacking into Yggdrasil, this was precisely the true function of the pair of horns given to Tia.

"...!"

Intense pain struck her head, causing Tia to frown. Yggdrasil was resisting, it was struggling, trying to evict Tia's consciousness that was invading in the form of electrical signals.

"Tia won't lose... This time, Tia will protect Yuu!!"

Using willpower as fangs, turning emotions into claws, Tia bit and ripped apart Yggdrasil's consciousness.

Tia's thoughts were endlessly amplified by the electrical energy obtained through the transmutation of dark matter, gradually conquering the core system.

The golden particles shrouding the surroundings shook. It was a sign that Yggdrasil's spirit body was starting to change.

'—Reject, reject, reject, unacceptable, overload, unacceptable—destroy, reject, reject—!'

Yggdrasil resisted desperately but the CPU had been destroyed physically, the mind was damaged, and right now, its computational power had dropped to its limit.

Conversely, after devouring Yggdrasil's consciousness, Tia's thoughts had acquired overwhelming processing power.

But due to excessive expansion of her ego, her original self turned fuzzy. Having obtained processing power that was originally impossible for humans to have, Tia's mind could not keep up with her thoughts.

"Tia is... what?"

Amidst her expanding ego, her consciousness was wavering.

But his words, carved deeply in her heart, kept Tia's consciousness together.

—You are a—cute, girl.

Tia gritted her teeth and used her dark matter to the limit to use her thoughts to rewrite everything.

"That's right... Tia... Tia will become Yuu's wife!!"

Then her will raced along the network formed from plants, exploring Yggdrasil's true nature.

Then she understood. The power to control electricity was merely one part of Yggdrasil's true nature.

The name of the authority was: Akashic Record.

There, Tia caught a glimpse of everything.

Part 6

Composed of golden particles, Yggdrasil's mind twisted and changed in shape.

The gigantic body, never collapsing no matter how many times Noah attacked, changed in form as though melting.

"Tia... What did she do?"

I looked in surprise but I was soon struck by even greater shock.

Shaking, gradually fading away, the Ether Wind proceeded to trace out a certain outline.

Instead of a giant tree, it was the silhouette of a young girl.

"Tia-chan...?"

Iris cried out in surprise.

Indeed—The golden particles were undoubtedly showing the figure of Tia Lightning.

"Looks like it's a success. Tia has already taken control of Yggdrasil's core."

Kili smiled happily and explained to us.

"What... Control of the core?"

Since it was too shocking, I could only repeat like a parrot.

"Yes, capable of outputting thoughts as electrical signals, right now, Tia can electrically interfere with senses, in other words, hack into Yggdrasil then tamper with the core, forcing the system to recognize her as the new core."

Kili replied so nonchalantly, but after seeing the Ether Wind fade away, she smiled.

"From the start, I raised Tia intending to have her devour Yggdrasil. But back then, I had no idea that Yggdrasil was such a terrifying monster. If we had challenged it normally, I think we would've failed already. It's all thanks to you inflicting damage to the core, Yuu, that we succeeded on this occasion."

The golden particles scattered amidst the sky's morning glow.

The particles showing Tia's image also disappeared gradually.

Visible under the particles was Yggdrasil's collapsed remains and a girl with a pair of radiant wings on her back.

Looking up at the young girl flying back to our side, Kili said proudly:

"Look, Yuu, this is the new dragon I raised—Tia Lightning Yggdrasil."

Epilogue

Turning time back slightly... The location was the Asgard research laboratory where Miyazawa Kenya served as director.

Swallowed into Yggdrasil's interference range, with all electrical systems down, the interior of the facilities was shrouded in darkness.

But in the fourth floor underground, an area where even starlight from outside the windows could not reach, there was an abundance of faint light for some reason.

The light source was inside the lab, on the other side of the opened partition.

Located in the center of the room, whose cooling system was down, there was an opened coffin.

Miyazawa Kenya was standing in front of the coffin, silently staring inside it.

However, footsteps were suddenly heard in the silent lab.

Then with a click, there was the sound of someone raising a gun.

"Freeze."

A stern voice shook the stagnant air.

"...Ah, speaking of which, the alarm system is down too. No wonder there are uninvited guests. Who are you?"

Miyazawa Kenya asked in a lethargic voice without even looking back.

"Not asking unnecessary things is the key to staying alive. Answer my question if you don't want to die."

Jeanne Hortensia threatened in a sharp tone of voice. Originally a member of Sleipnir, this girl had quietly infiltrated the laboratory by seizing the opening when Yggdrasil had downed all electrical systems.

In order to seize the secrets in this lab where they had been forced to retreat from at one point, Jeanne chose to work separately from Kili.

"Yes yes. Please ask whatever you wish to ask. I will answer any question, because dying means I won't be able to continue my research."

Despite facing a life-threatening crisis, Miyazawa Kenya showed no fear at all.

Her golden eyes alternated their gaze between Miyazawa Kenya's back and the glowing coffin. Then she said:

"Do you know anything regarding Hreidmar?"

"...Hreidmar? I am hearing this name for the first time."

"Then what about 'Fafnir'?"

Jeane then asked this question. Miyazawa Kenya pondered briefly.

"Fafnir... Speaking of which, I've heard rumors before that NIFL was carrying something called the 'Fafnir Project.' I recall that the project was based on a hypothesis on the scrapped authority, Code Lost..."

"Scrapped authority?"

"Just as dragons possess special powers, humans might have some kind of lost special power—An unverified hypothesis born from that kind of hope. Since I was not too interested in this hypothesis, I don't know any further details."

Hearing his answer, Jeanne brought her hand against her mouth and murmured to herself: "I knew it. It's necessary to search NIFL facilities to find out more details, not Asgard ones..."

"Have you asked everything you want?"

Hearing Miyazawa Kenya, Jeanne looked up.

"No, not yet. Cough up what research you are conducting here. Compared to other facilities, this lab has too many suspicious things about it."

"...This is a lab belonging to Asgard, the international organization on dragon policies. Obviously, dragon research is being carried out."

Miyazawa Kenya shrugged and answered.

"Then what's inside that glowing box?"

Jeanne looked at the faintly glowing coffin and asked.

"A cadaver."

"...Cadaver? What kind of cadaver exactly?"

"Since it's dragon research, of course this is a dragon cadaver, right?"

"What—"

Jeanne gasped and slowly approached the coffin.

"...I will confirm. Don't move."

Jeanne warned Miyazawa Kenya while moving to a position to look into the coffin.

What was kept inside the coffin was a thick silver tentacle with a bulging midsection. Roughly the size of an adult, its two ends were cross sections from being ripped apart. Faint purple light was escaping from inside the tentacle.

"This is..."

"Remains of the purple dragon—'Purple' Kraken. Two years ago, two Krakens were taken out, resulting in a large number of tentacle remains drifting in the ocean. In addition to being a useful resource, the mithril tentacles are also precious samples, hence Asgard collected those remains as much as possible."

Miyazawa Kenya explained nonchalantly and pointed his finger downwards.

"The lowest level in the facility is a giant swimming pool where a large number of Kraken tentacles are preserved. However, among all these remains, this one is special."

His eyes blazed with the flashing light of curiosity while he pointed to the coffin and spoke.

"Special?"

Jeanne asked nervously.

"This is definitely a cadaver, the remains of Shinomiya Miyako, the D who had turned into a Kraken. It's just that despite the fact that this tentacle is a cadaver, it also has life."

"What are you talking about? If it has life, it's not a cadaver, right?"

Jeanne frowned. Smiling wryly, he answered:

"You don't get it? Maybe I didn't explain enough. What I am saying is that there is life residing inside this cadaver. The light inside the tentacle... That is precisely the light of new life."

"New life...? Don't tell me—"

Jeanne was speechless. She gazed at the unnaturally bulging tentacle.

Miyazawa Kenya nodded at the stunned Jeanne then spoke solemnly:

"Indeed, residing inside these remains is the child of the Kraken's mate."

*

Riding in a large van, we drove east towards the horizon where the rising sun was shining.

The driver was the middle-aged woman who was part of Asgard's staff. Shinomiya-sensei was sitting in the front passenger seat.

We, the students of Brynhildr Class, were sitting side by side in the spacious back seats.

"Tia-chan still hasn't woken up."

Looking at Tia who was sleeping while leaning against me, Iris said with worry.

Having taken control of Yggdrasil's core, Tia had lost consciousness after returning to our side.

After taking Tia to meet up with Shinomiya-sensei, we were now riding the van back to the lab.

"Don't worry, Tia had definitely retained her sense of self when she returned to us. She also successfully endured the strain during the hacking process, so she should be waking up soon."

Sitting next to Iris, Kili quietly explained.

"By the way, why are you getting a ride too?"

Lisa looked at the seating which had become slightly crowded due to Kili and asked.

Since Kili had boarded the van as though it were the most natural thing in the world, no one spoke up about it earlier.

"I have matters at the lab too. Jeanne-chan... No, John should be waiting there for me."

"John?"

I asked Kili in surprise.

"Yes, so give me a ride there. I already helped you guys out, so it's not like you have a problem with letting me relax for a bit, right?"

Kili shrugged and asked everyone.

"...Indeed, it is true that Kili-san helped us immensely. We will take you to the research lab."

Mitsuki accepted Kili's request despite a reluctant expression.

"However, is it really okay for us to return just like that? The remains of Yggdrasil's main body and roots are still there..."

Firill looked out the back window—at the western sky—and said.

Ariella nodded and agreed with Firill.

"I'm worried too. Now that you brought it up, I'm still not clear on the situation. Although Tia has seized control rights to Yggdrasil's core, but what happens next...?"

Hearing this question, Kili shrugged.

"Tia has become the administrator of the gigantic system that is Yggdrasil. Although I still don't know how much of that power she is able to control... At least, there's no more need to worry about Yuu getting controlled."

Hearing her say that, Ren looked reassured.

"...Thank goodness."

Ren said quietly, staring at my face.

"Onii-chan, is it okay now?"

"Yeah, the feeling has returned to my left arm. It should be able to move freely once the cast is taken off."

I nodded at Ren and rotated my left arm to show her.

"Mmmm..."

Perhaps because my movements were felt by Tia, she moaned slightly.

"Tia?"

I called her name. Tia opened her eyes slightly.

"Yuu...?"

Tia stared blankly at my face.

"Yeah, it's me."

I nodded in response. Showing an expression like she was still in a dream, she said:

"Yuu... Tia saw many things when inside Yggdrasil, but... almost can't recall anything."

"That's fine. Tia, you just need to remember that you're Tia. No need to force yourself to remember."

I stroked Tia's soft hair and tried my best to speak in a gentle tone.

It was impossible to imagine how massive the volume of information flowed into Tia's mind when carrying out a hacking attack against Yggdrasil's gigantic mind. Trying to get a full grasp of all that information would probably stop the brain from functioning normally.

"But... There seems to be something Tia must say... A message that must be passed along."

"Even if that's the case, there's no need to rush. Rest properly and wait until you regain your energy."

"Yeah..."

Tia nodded uneasily but at this moment, her face looked like she suddenly thought of something.

"—Oh, I just remembered one thing."

Tia said and tears flowed out of her eyes.

"Eh? W-What's wrong?"

I asked her frantically. Tia immediately wrapped her arms around my neck and hugged me tightly.

"What Yggdrasil did to Yuu... Tia saw it. So many, so many... precious memories taken out. Yuu must be suffering so much..."

Hearing Tia whisper quietly in my ear, I could not help but gasp.

Iris and the other girls were watching Tia who had suddenly started crying.

Then only loud enough for me to hear, Tia continued:

"Don't worry, Tia will return the memories—back to Yuu."

Badump, my heart pounded intensely.

What I felt at this moment was... not "Mononobe Yuu's" joy of possibly recovering the past, but my current self's—

Fear, not knowing how my feeling towards Iris might change.

Afterword

This is Tsukasa. By the time I noticed, 6 volumes have already been released. With so many scheduled trips this summer, it feels kind of like time went past in a flash.

Getting invited to take part in a Taiwan event was my first time leaving the country ever. Since I've never even taken a plane before (I apparently took a flight once in my childhood, but it doesn't count since I don't remember it) so everything felt so fresh.

Oh my, a plane really flies in the sky... Although that's only logical, seeing the scenery tilt for real and the ground gradually getting far away, it's truly breathtaking for me.

Sure enough, there are many things which are hard to understand without experiencing them.

I originally thought that Tokyo's summers were very hot, but Taiwan is even hotter. It made me feel poignantly that I've really arrived in a different country. Then my next surprise was the number of vehicles and that traffic lights showed seconds to countdown. There were so much scenery I wouldn't normally see.

But when I came to an anime shop, I saw many characters commonly seen in Japan arranged inside. There was even an extra large poster of Fafnir!

The event was so crowded and bustling it was like a doujinshi fair in Japan, especially the lively atmosphere centered around young people. And all the readers attending the Fafnir autograph session were very enthusiastic and welcoming. I had a very happy time there.

...Oh, this is totally a Taiwan trip report, or more like a "summer vacation reflection" (sweats).

I was very bad at writing picture diaries or book reports for summer vacation back in school, so I'm not confident whether I can write these kinds of reports in an interesting way... Anyway, I would be deeply honored if I succeeded in letting you feel my joy slightly.

Then after returning to Japan, every day was extremely busy for me, either attending a doujinshi fair or having meetings for the anime.

That's right... The anime adaptation is progressing step by step! Recently, the meetings have gotten frequent, making me finally feel that my work is being animated for real... Scheduled to air next year starting January, please check out the book band for this volume to see the details.

My feelings are so similar to when taking a flight.

While on a flight, I kept looking at the screen showing the altitude, speed, temperature and current location. I felt a sense of surreal elation at the situation of flying 9000 meters in the air at almost 800 kilometers per hour.

It was a floating, restless feeling, perhaps it might be easier to describe it this way.

Amidst this massive project of an animated adaptation, it's like being on a plane flying at immense speed across the sky and afraid to look "outside."

But it's a loss if you take a plane without looking out the window, so I intend to enjoy things properly, doing everything I can, working hard to create a good product, so please show your support.

Also, Fafnir's manga adaptation, serialized in Good! Afternoon magazine, is currently entering the climax of the Leviathan battle. Leviathan is super impressive, it's so cool looking! The manga's first volume will be released for sale at the same time as the novel's sixth volume, so I'd be overjoyed if you could read both together.

Then next are acknowledgements.

Korie Riko-sensei, thank you for drawing so many charming illustrations of Ren in this volume, I'm so grateful to you! It's so happy to see Ren have so many expression since she did not have a prominent part in the story until now. Of course, it's not just Ren. Iris and the others are very cute too, it's too awesome!"

Editor in charge, Shouji-sama, thank you for your amazing draft correction advice for this volume as well. Thank you for looking after me during the Taiwan event and anime meetings, I'm truly grateful to you. Things seem like they'll get even busier from now on, I look forward to us continuing to work together.

Then I have to express my utmost thanks to all the readers cheering for me. See you next time.

Tsukasa, August 2014

Illustrator's Afterword

I drew so many illustrations of Ren-chan this time!!

I really wanna hear Ren-chan call me Onii-chan (Onee-chan) (°∀°*)

Korie Riko

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