Matsumae

Matsumae is a teacher at Seinan Gakuin High School and the homeroom teacher of Shuu Tsukiyama. She is also a Ghoul in the employment of the Tsukiyama family.

She's responsible for keeping an eye on Tsukiyama while acting as his teacher. She's shown to keep a cool head, even when surrounded by ghoul investigators, and commanded her group of ghouls in combat. Like her master, Matsumae retains a professional behavior even when under what is normally considered pressuring, such as a CCG extermination.

(Source: Tokyo Ghoul Wikia)