Female Height: 290cm Age: 38 A math teacher and a strict disciplinarian with a coercive and cruel personality (though she occasionally shows a clumsy and playful side). She possesses superhuman strength, capable of smashing podiums or walls and piercing a student's skull with her compass in one go. She kills failing students. True to her name 'Circle', her left arm is a sharp compass (which is actually Mr. Compass). She loves Oreos very much. The things on her head are horns, not animal ears; since the horns look like cat ears and she often has a 'cat mouth,' the fandom sometimes depicts her as a cat.

Male Height: 290cm Age: 39 He is the compass attached to Miss Circle's left arm and can transform into a compass. He loves KitKats very much. When he gets angry, his eyes sometimes turn into light blue cat-like eyes.