Amane Minase - The voice actress we already know. Not much to add, we saw the most of her story. She is just more offensive now, and doesn't shy away from kissing Kazu and being near him.
Isami Shirasagi - The other childhood friend, a sweet tomboy who has a crush on Kazu ever since they were in the Dojo together. She pretends to be a guy, Rua's new BF, to make Kazu jealous... but it backfires on Rua, since this just makes Kazu and her reunite.
Suzuka Kocho - The student council president, a ladylike girl who is not afraid to work on her own and get dirty. Kazu sees her cleaning the school yard everyday and decides to help her. I don't remember if there was any romance between them yet, sorry.
Ayaka Ayukawa - The gal we saw in the karaoke bar in Ch1. She ends up working part time together with Kazu, doesn't like him at first since she is Rua's friend. But falls in love with him after Kazu saves her from Rua's henchmen (the pig gets jealous for no reason ofc). Even tho we didn't see her laugh at him in ch1, she apologizes for it, but Kazu didn't mind.