Mitsuo is a freshman studying law attending the same university as Banri. After the entrance ceremony, heading for freshman orientation, he gets lost on the campus, and meets and befriends Banri. Banri calls him "Yana-san". He has been the target of Kōko's obsessive, one-sided affection since their elementary school years. He secretly took the exam to this university in an attempt to escape from her. He lives alone in an apartment three train stops away from Banri's.