Dai Densetsu no Yūsha no Densetsu:Volume 1 Translator's Notes

Chapter 1

Snow Joke

↑ What Ryner meant was that the likelihood of him getting pumped up was as low as the likelihood of snow falling tomorrow (contextually inferred to be impossible); hence he made the joke that it's going to snow tomorrow since he's getting pumped up here.

Ahotaare

↑ Ahotaare is derived from Sion's original family Astal, which is romanized as Asutaaru. "Aho" (あほ, アホ, 阿呆) refers to idiot and is a word originating from Kansai dialect.