Kimizuka Kumiko

The protagonist's classmate.
She used to be childhood friends with both the protagonist and Nakamura Yuuri, but now turns a blind eye to the latter's bullying.

While her cheerful, loud and tomboyish personality has not changed compared to ten years ago, she has undeniably acquired some girlish charm on the way.
Kumiko has many friends both outside and inside the school, though some of them are rumoured to be rather shady.