Toudou Hijiri attends Koua Academy, a front for the assassin-training organization Kritiker. His psyche bears deep scars from witnessing his mother murder their family, leaving him emotionally fragile and resistant to violence. Operating under the codename "LaPerm," Hijiri grapples with his role as a trainee assassin, exhibiting timidity, vulnerability, and pervasive self-doubt regarding his worth and masculinity. These insecurities intensify his romantic fixation on fellow student Sena, fueling possessive jealousy, particularly towards Sena's interactions with older males like Aya.

Hijiri's journey sees him evolve from a hesitant recruit into a more decisive operative, undertaking missions alongside the established Weiß team despite his instability. His bond with Sena shifts towards protection, yet remains complicated by emotional dependence and unresolved trauma. Ultimately, Hijiri chooses to abandon Kritiker, seeking a life beyond its violence and manipulation.