Ranka Sena governs Yuihime Girls' Academy as principal while raising her daughter Airi single-handedly. Celebrated by students for her approachable yet authoritative presence, she enforces rigorous standards even when personally conflicted. Her ambitious push to integrate Yuihime with Kagamidai Private Academy sparks fierce resistance from Airi, who clings to the all-girls environment. Unswayed by their disputes, Ranka champions the merger, convinced of its strategic value.

Divorced for over ten years, Ranka’s relentless dedication to the academy keeps her occupied until late hours, leading Airi to live independently—a testament to her prioritization of professional duty.

Her personal life holds contrasts: a steadfast friendship with Yuiko Amaha exists alongside an unspoken antipathy toward Yuiko’s daughter Miu, adding tension to their interactions.

Ranka’s physical traits include a 166 cm stature, AB blood type, and measurements of 89-60-87. Auburn hair and vivid pink eyes accentuate her distinctive demeanor within the academy’s halls.