Height: 290cm. Female, math teacher. She is a strict disciplinarian with a coercive and cruel personality, though she can occasionally be lively and playful. True to her name, her left arm is a sharp compass. She brutally kills students who break the rules or fail their exams. She loves Oreos. The things on her head are horns, not animal ears. Because her horns look like cat ears and she often has a 'cat mouth' expression, the fandom sometimes depicts her as a cat.