Kou is Ikumi Kyouko's cousin and fiancé.

He is older than she is and often, much to her chagrin, tries to take care of her. He is dependable and mature, though Kyouko claims that he is not. His attempts to get closer to Kyouko often backfire and she ends up resenting him more, though it was clear that they were very close growing up.

Kou sees that their relationship is very strained and even goes so far as to suggest calling off the engagement, since he would rather not be hated by Kyouko who he harbours feelings for still.

He meets Okudaira Akira on a group date and finds her to be cute though childish. He eventually keeps bumping into her and spends enough time with her for people to start speculating that there is something going on between them.