Female Height: 290cm Age: 38 Mathematics teacher. A strict disciplinarian with a coercive and cruel personality (though she occasionally shows a clumsy or playful side). 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 kills failing students. She loves Oreos intensely. The things on her head are horns, not animal ears; however, since her horns look like cat ears and she often makes a 'cat mouth' expression, the fandom sometimes depicts her as a cat. She has long, pointed black hair that reaches down to her knees.

Female Height: 270cm Age: 35 Language teacher. Characterized by the alphabet blocks on her head. She has sharp claws and uses both hands as weapons to scratch and tear students to death. 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. She has messy, shoulder-length black hair.

Female Height: 178cm Age: 36 Science teacher. Her weapon is her left arm, which is a box cutter. She slashes and kills students who fail their exams. She has short black hair with straight-cut bangs and a strange black horn on her head tilted to the left. Her hair is tied into a small ponytail with a white ribbon.