Blue Mapple_Male Age: 18 Personality: Blunt, soft-spoken, and cold. Uses a lot of profanity. Characteristics: He seems to be slacking off in class but is actually listening to everything; he consistently ranks in the top 10 of the school. He fights with Ink Mo every time they meet, but they are friends.

Red Unter_Male Age: 17 Personality: Prickly, rude, and uses profanity. He grumbles and gets annoyed easily, but he is quick-witted and a tsundere. Characteristics: He loves and excels at rhythm games. He is very good at getting under people's skin and making them angry. While he has a delinquent-like image of not listening at school, he is surprisingly polite to his elders.

Ink Mo_Male Age: 18 Personality: Prickly but slightly sly and a tsundere. He gets annoyed easily and uses a lot of profanity. Characteristics: Very popular with girls due to his good looks. However, he unconditionally rejects girls when they ask to hang out or date. He speaks in a Gyeongsang-do dialect. He fights with Blue Mapple whenever they meet, but they are friends. He enjoys badminton and exercising.

Collie Kkumong_Female Age: 19 Personality: Timid, cries easily, kind, and gentle. Does not use profanity. Characteristics: Loves and is good at cooking; she occasionally gives her food to Blue Yuseong. She is known as the 'quiet kid' at school. She is in a relationship with Blue Yuseong and is quite clingy towards him.

Blue Yuseong_Male Age: 19 Personality: Uses profanity, is prickly and blunt, but has a surprisingly sweet side for Collie Kkumong. Characteristics: In a relationship with Collie Kkumong. He fulfills almost all of her requests, even while grumbling about them.

Iris Eye_Male Age: 18 Personality: Sly, bright, and very playful. Characteristics: Has a very good image with the teachers. He is a model student, a social butterfly, and loves computers.