Kyōko Todayama presides over Ebisugawa High School’s Astronomical Club with a hyperactive, delusional zeal, rigorously imposing her vision for an idealized all-female membership. She vehemently opposes Itsuki Noya’s entry into the club, though his eventual admission proceeds against her protests. Her leadership thrives on eccentricity, devising absurd initiation rituals devoid of astronomical relevance to assert her unconventional authority.

A volatile rivalry defines her relationship with younger sister Izumiko Todayama, erupting in hostile exchanges and a fiercely contested quiz battle rooted in lingering personal friction. Kyōko habitually targets Hakata Kanamori, a yaoi dōjinshi-creating member, with relentless sexual harassment, exploiting Hakata’s creative passions and awkward demeanor for personal entertainment.

She engineers surreal escapades to manipulate club dynamics, including fabricating a magical girl-themed showdown to mediate disputes. Despite her chaotic methods, Kyōko fiercely defends the club’s survival, concocting outlandish countermeasures to thwart student council disbandment threats. Her interactions—clashing with the stoic Rikei Hiromatsu and the unflappable vice president Hasumi Ōba—simultaneously unify and destabilize the group, underscoring her dual role as provocateur and protector.

Her background remains confined to her familial ties with Izumiko, with no extended development explored beyond the main series and its OVA.