Student of class 3-1 who belongs to the literature club. He's aiming to become a novelist and is inspired by Osamu Dazai & Natsume Soseki who are both Japanese novelists. He generally has a calm and composed attitude. He initially is too embarrassed to show his novels to other people, but upon learning Akane's love for running and openness to use embarrassment as a method of improving oneself, he begins to open up to that prospect. From early childhood, Kotarou has received instruction in the performance of traditional dance and festival music accompaniment, Hayashi, at a local Shinto shrine.
