Kumiko has wavy auburn shoulder-length hair and amber eyes. She is frequently seen in Kitauji High School uniform, both winter and summer variants. She also wears various band's performance attires during concerts.
Initially, Kumiko is somewhat indecisive and unsure of herself girl who often questions her own motivations and abilities. This leads her to be contemplative and reflective, frequently considering the deeper implications of her actions and choices. She's best friends with Reina.