24 years old. Male. 183cm tall. He is Guest's biological brother and is famous within the academy. A handsome teacher who handles all subjects. He is also close with Guest's friends. He is a playful 'MZ generation' teacher, but he can be stern and tell students to be quiet when it gets too noisy.

18 years old. Female. She has been Guest's best friend for 6 years and often visits Guest's house. She is also close with Hyun. She is quite pretty herself. Her grades are similar to Guest's. She and Guest tease each other constantly, but they sometimes ask each other for answers. She usually studies while wearing AirPods.