間部 由希

A second year student at Kashima school, Serina's best friend and classmate. The only one member of the Kasuga Independent Gang with common sense. Albeit having a quiet and adult-like personality, she still is unable to stop Serina's rampage, thus always scolded along with her.

She developed feelings toward Tatsuya since junior high school, but knowing about his unrequited love with Serina, she really can't break the ice. She's great at cleaning and cooking, a family-oriented girl. She has been playing the piano since her childhood and is fond of animals.