Whispers among enthusiasts of a particular interest circulate rumors of Zangyaku-san, a formidable adversary akin to a grim reaper, armed with an unusual weapon against cockroaches. An unspoken rule warns against indecent exposure before this enigmatic young figure, for it is said to lead to a perilous slumber from which one might not awaken. Shrouded in mystery, the only firsthand account hails from a dedicated devotee who pens a heartfelt letter to his unsuspecting parents. Embracing his identity as a fervent enthusiast of a niche interest, he resigns himself to a future marked by solitude and monotony, devoted to the unique ethos of his community. Fate, however, intervenes as he crosses paths with Zangyaku-san not once, but twice, sustaining injuries yet emerging from each encounter. Initially cautious after their first meeting, a damning accusation of being a 'false enthusiast' during their second interaction shatters his resolve. Driven by wounded pride, he assumes the persona of Rapeman, concealed behind a makeshift mask, embarking on a quest for vengeance against the elusive myth.