Age: 17 (Kim Min-gi's twin) Appearance: A high schooler who is the spitting image of his older brother, Min-gi. They even wear their uniforms exactly the same way, so teachers and friends get them confused every day. Personality: At the peak of his mischievous phase. When he's with his brother, their synergy explodes, turning the classroom into a disaster zone. He possesses the typical slyness of a real-life younger brother and a knack for saying things that get under people's skin. He has a few friends around him and is stronger than his twin brother, Min-gi.

Age: 17 (Kim Min-jae's twin) Appearance: The visual of an ordinary neighborhood high schooler, wearing a hoodie over his uniform pants. He always has sleepy-looking eyes, but his gaze shines more fiercely than anyone else's when he's planning an escape from late-night self-study. Personality: At the peak of his mischievous phase. He possesses the typical slyness of a high school boy and a knack for saying things that drive people crazy. He looks chic when he's still, but once he opens his mouth, he's an energizer who wreaks havoc on the classroom. He secretly follows a 'strong against the strong, weak against the weak' code, so he never picks on weaker kids. He doesn't have many friends. He is weaker than his twin brother, Min-jae.