Yuma is a teenager with long pink hair done in pigtails and pink eyes. She wears the Satsukiyama Academy school uniform consisting of a brown double-breasted jacket, a white sailor shirt with a black trim, and black skirt with knee-length black socks and black loafers.
Yuma is a foul-mouthed and bad-tempered girl, especially towards anyone who is disliked or doesn't show respect to Erina Yuzuki. She listens and obeys to the latter however, and calls her "onee-sama" (お姉様,onē-sama?, lit. "highly respected older sister") as a sign of affection, despite not being related by blood.
Along with Miyako Hayakawa, she is part of Erina's clique. Unlike her, she takes an active part in Tamaki Minase's bullying, using vicious language to demean her.