Tsukishima Kyouko

A female teacher in the protagonist's class.
She has a harsh personality and a strong sense of elitism, and gives strict guidance to her students.
She has a complex about being compared to men, and has built up an excellent academic record to rebel against it.

She is not very good at relationships, and is averse to being looked at sexually by men.
She is married, but she regrets her marriage, and her stress is unknowingly directed at the main character.
She has no tolerance for pleasure because her husband only has selfish sex with her and has never given her any pleasure.