The physical education teacher at Yokai Academy and a kraken. He is also a way worse pervert than Gin will ever be, as he goes after the female students. Mizore once confessed to Kotsubo that she liked him and he tried to take advantage of her, resulting in the latter freezing him. When he returns, Kotsubo effortlessly attempts to pin the injuries of two students on Mizore to have her expelled and tries to kill her when the plan failed. With the help of Moka's blood infusion and the borrowed vampire power, Tsukune soundly defeats him and exposes the truth to the whole school. In the anime, Mizore never had feelings for Kotsubo and was instead almost taken advantage of when she was crying over Tsukune.

(Source: Wikipedia)