Ume Shiraume

She is from a wealthy family who decided to attend the same high school as Hana Oshiroi. Apparently they've been "close" friends since elementary school. It is heavily "implied" that Ume Shiraume is a lesbian. She's often seen abusing Yo Sato when asked Oshiroi to do something misleading such as "borrowing" her school uniform. For some reason, Ume Shiraume is a first year student and yet she came the student council president. She probably won the seat by  a "probably rigged" election. Other strange "facts" about her. Ume Shiraume also bathed with Hana Oshiroi many times. Instead of being angry with Shaga for teasing Oshiroi, Shiraume, instead, decided to "bath" with Shaga and forge some "bond" with her much to Shaga's dismay. Ume Shiraume seems like a capable fighter at first glance; however, unlike Sato and the other characters. She doesn't participate in Half-priced lunch fights.