Takamine Saya

The protagonist's homeroom teacher whose subject is math. She always keeps a close eye on the protagonist.
She is an excellent teacher with an arrogant attitude. But she isn't used to being passive and is not good at receiving punishment.
Every since birth, she's been educated to be superior to others, so she has a dominant attitude, despite this, she comes across as childish.
Although a beautiful woman, she is feared by her students due to her high standards that doesn't hesitate to look down on students who don't meet them.
When it comes to sex, she is completely innocent. She never even masturbated before.
She is Takamine Miyu's older sister.