Kotomi Asakawa is a twelfth-grade student distinguished by her red shoulder-length hair with V-shaped bangs and blue eyes. Her physical traits include a slim build, pale skin, and medium breasts. She typically wears a school uniform, often accessorized with a ribbon—specifically a yellow hair ribbon in depictions—and occasionally appears in a one-piece swimsuit.

Personality-wise, Kotomi is refined, kind, and friendly. Raised in a strict household with enforced curfews, she is universally regarded as "perfect" in appearance, figure, personality, and academic performance, making her an admired figure within her social circle.

Her background establishes her as a childhood friend of Munemitsu Soga, who harbors obsessive admiration for her. Kotomi recalls Munemitsu was once sweet but transformed into an antagonistic figure under his father’s influence. She shares a close bond with protagonist Kenta Kogure, who has a crush on her, positioning her centrally in their interpersonal dynamics.

The narrative involves Kotomi among ten individuals confined in an abandoned school building. Her presence begins after she sends Kenta a letter summoning him there, though adaptations vary regarding her reasons for being present. In the OVA *Isaku Respect*, she is coerced by blackmail threatening exposure of personal secrets. Once confined, she becomes a target of Isaku, the janitor orchestrating their imprisonment. Kotomi navigates threats from Isaku and volatile relationships with others, particularly Munemitsu’s jealousy-driven violence toward Kenta over her.

Her role centers on escape attempts with the group. Outcomes diverge: some paths involve her capture and assault by Isaku, while others depict her freedom. A "golden ending" implies potential romance with Kenta post-escape. The confinement’s escalating tensions expose her to psychological stress, though her character development across adaptations remains undefined.