Takamine Saya♀

Elite math teacher who looks down on students. She is the Rhythmic Gymnastics club adviser. She was born into a prestigious family and grew up with a gifted education. Although a fully certified teacher, she is the youngest of her peers due to skipping two years while she studied abroad.
A woman who looks down on students who don't meet her standards. She is the member of 'Student Quality Control Committee' which is formed by teachers concerned about the academic performance of some of their students. The protagonist is one of her targets and she rain scorn upon him. Most of the students are not fond of her for her terrible personality.
She is Takamine Miyu's older sister.