Yuka Iseda commands authority as Ebisugawa High's student council president, balancing a tsundere blend of sharp-tongued strictness and concealed emotional fragility. She leads relentless campaigns to dismantle Ebisugawa High's Astronomical Club, citing their eccentric activities as breaches of school decorum. Though her disciplinary drives often crumble against the club's united front, her dogged enforcement reflects a deep-seated reverence for institutional order.

Beneath her combative persona simmers an attraction to Hasumi Ōba, the club's unflappable vice president. Their dynamic oscillates between public clashes and fleeting moments of connection during heated debates, with an official illustration capturing them mid-escape, fingers intertwined—a rare glimpse of vulnerability that complicates Yuka's rigid principles.

Her meticulously crafted authority unravels at the sight of cats, a debilitating ailurophobia weaponized by opponents. During one confrontation, Astronomical Club strategist Rikei Hiromatsu unleashed a feline battalion, reducing Yuka's imposing demeanor to panicked retreat—a recurring weakness that underscores the irony of her otherwise unshakable facade.

Yuka's personal history remains veiled across official narratives, with no expansion on her origins or transformative arcs. Her story orbits persistently around clashes with stargazers and silent glances at Hasumi, framing her as both antagonist and conflicted ally. This duality amplifies her role as a counterbalance to the club’s whimsy while leaving her unresolved tensions simmering beneath administrative rigor.