Kiyori is Sumika and Ushio's best school friend whom not much is known about. She is always seen with them at school, however, and accompanies them on various outings.

She is in the music club in school, and she does not spend a lot of time outside with either Sumika or Kazama because of her club activities taking up most of her time.

Kiyori has a cheerful demeanor and is always eating or snacking. She isn't interested in girls but is well used to the fact that her friend is a lesbian. She does seem exasperated (like most others) of Ushio's fleeting crushes and constant talk of wanting a cute girlfriend. She is supportive to Kazama and the formation of the Girls Club; doesn't enter but stays with them because "It might be fun".

Her biggest complaint is that Sumika's occasional jealousy-induced awkwardness with, sadness around, and meanness towards Ushio spoil her desired peaceful lunch. Lunch is very important to her, like most foods.

Kiyori seems vaguely aware that Sumi's feelings for Kazama are not entirely platonic, and on occasion, she tries to exclude herself (and sometimes others) from the two so that they could spend more time together. Though this also may just be coincidence; Kiyori's actions and motives rarely are expounded upon and she seems far more concerned about having fun and munching on snacks rather than unnecessary emotional melodrama.

She often uses the phrase "I kindly decline!" followed by a melodramatic fake laugh.