Aila Hatsuse serves as the twin brother of Karila Hatsuse, a central figure in the series. He is enrolled at Sendou Academy, where he actively participates in both the Opera Club and airsoft engagements. Leveraging his refined acting abilities from the Opera Club, Aila adeptly mimics his sister Karila's appearance and mannerisms to the point of seamless impersonation. This skill occasionally sparks confusion or creates strategic advantages during encounters between rival academies. Despite their twin status, Aila and Karila display markedly divergent personalities: Aila maintains a polite demeanor and distinct self-presentation, contrasting sharply with Karila's tomboyish and hot-blooded temperament. The surname "Hatsuse" adheres to the series' thematic naming tradition, drawing from the Shikishima-class battleship Hatsuse.