Kazuyuki Mitani

A senior in high school and older step brother of Futaba. He met Futaba when he was a kid and befriends him with the motive of hurting him due to his mother dying from stress and drugs over her divorce. Seeing a sad Futaba when he was expecting a happy person, his feelings changed but a part of him still stuck to his motives. Later on, he inevitably moved in with Futaba and his stepfather, deciding to make himself hate Futaba.