Ukobach

Ukobach is Mephisto's familiar and a stove spirit who prepares Rin and Yukio's meals. He developed a close bond with Rin through their mutual love for cooking.

Ukobach is a minotaur like demon. He has been seen to transform into a bigger minotaur and appears from thunder strikes (for a comedic effect of some sort).

Ukobach is proud of his cooking skills, but also fiercely protective of his food and his domain, the dorm kitchen. As such he was enraged at Rin for using the dorm kitchen without his permission and for a while he refused to cook for the brothers. He also tried to cook 3 girls for ruining his lunch for Rin and Yukio. He is often silent, but Rin has been able to communicate with the little demon and the two get along well due to their mutual love of cooking.