Okuto Kotsubo(小壷 奥人, Kotsubo Okuto) is the physical education teacher at Yōkai Academy and a kraken. Mizore once confessed to Kotsubo that she liked him and he tried to take advantage of her, thus she froze him. When he returns, he effortlessly attempts to pin the injuries of two students on Mizore to have her expelled and tried to kill her. 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.
Though a corrupt and violent teacher in both mediums, the kraken's personality varies quite a bit. In the manga, he is laid-back and mocking, while in the anime he at least puts up the facade of a professional, caring gym teacher. In the anime he also molests Mizore after seeing her upset and eventually being frozen by her.