She is a senior of Class 9 and a member of the Athletics Club.

Isahaya is a nice girl most of the time, but is capable of being very nasty when she feels jealous. She also has a mentoring side, as she watches out for her underclassman Ariake after she gets over her initial dislike of the younger girl.

Isahaya wears the standard girl's uniform of Hakoniwa Academy, as well as the uniform of the Athletics Club. She has dark green eyes and brown hair (black in the anime) tied in a short ponytail and held with a clip. Isahaya is left handed.

(Source: Medaka Box Wiki)