Hikari Hazakura, a 22-year-old physical education teacher at Kawanuma East High School, later transfers to Sakikawa Senior High. She balances advising the student council with coaching the swim team, her athleticism shaped by a lean 164 cm frame, 53 kg weight, and measurements of 88-56-87. Her shoulder-length dark hair is often tied in a half ponytail secured by a white ribbon, complementing bright blue eyes and sun-kissed skin marked by pale swimsuit tan lines.

Raised alongside Takashi Takahashi and Nana Nanjo in the same apartment complex, her childhood brimmed with mischief—pinning Takashi in playful wrestling matches or coaxing him into girls’ clothing. Initially viewing him as a younger brother, her perspective shifts during a joint school festival with Kawanuma West, where she confronts budding romantic feelings, sparking a relationship that transitions their bond from familial teasing to heartfelt partnership.

Hikari’s lively, prank-loving nature masks a bashful clumsiness in romantic moments, endearing her to students who admire her blend of approachable confidence and relatable vulnerability. As a mentor, she prioritizes teamwork and camaraderie, drawing from her amateur swimming background to inspire athletes. Her career advances in later arcs, including a role at Sakikawa High during the "Kurisu Kurumi Arc."

Her dynamic with Takashi evolves through mutual recognition of deeper affection, their banter softening into tender gestures. Struggling to reconcile her bold persona with newfound emotional openness, Hikari navigates the tension between her assertive exterior and the vulnerability of accepting both his maturity and her own shifting heart.