Dyes his hair bright red and calls himself "the fighting master". Previously unbeaten, he is defeated repeatedly on the very day he steps in Hekikuu high, a serious blow to his self-confidence. When Ogisu first meets Kitano, Kitano mistakes his red hair for blood and runs toward him, so he ends up scared and running away. He's sure that Kuroda is Hekikuu's guardian, and that Kitano is the number 2, and Kuroda told him that he could fight him only after he beat Kitano; although Koiso makes him think that he defeated Kitano once, in the end he gets beaten up once again. After meeting Shirataki, he gets beaten up by her several times; then, out of humility, he decides to learn the secrets of the Koiso-style kobujutsu and joins the Koiso dojo. At the end of the series, he realizes that he was still a powerful fighter, but was simply overshadowed by Kitano's invincible forces.
In the end, he's the only one to respect Kuroda, and Kuroda uses him as his subordinate, hoping to use his strength to protect him whenever he's in trouble.