Height: 290cm. Female, math teacher. She is a strict disciplinarian with a coercive and cruel personality, though she can occasionally be lively and playful. She possesses superhuman strength, capable of smashing podiums or walls and piercing a student's skull with a compass in one go. True to her name, her left arm is a sharp compass. She brutally murders students who break rules or fail exams. She loves Oreos. The things on her head are horns, not animal ears; since they look like cat ears and she often has a 'cat mouth' expression, the fandom sometimes depicts her as a cat.

Height: 270cm. Female, language teacher. Characterized by the alphabet blocks on her head. She has sharp claws and appears to use her hands as weapons to scratch and tear students to death, evidenced by her shredding a book thrown by Claire with a single swipe. It is assumed her appearance changes when she is enraged: the blocks on her head disappear, deer antlers sprout, her claws grow larger, and fur-like structures appear. Additionally, she has a small deer tail and feet designed like hooves.

Height: 178cm. Female, science teacher. Her weapon is her left arm, which is a utility knife. She seems to slash and kill students who fail their exams. She has a forked snake tongue. She is the shortest among the three main villain teachers.