The class president. He has a strong sense of justice and responsibility, so he keeps the students organized. He occasionally shows a human side of weakness. He has such handsome features that he's called the school idol. Kind to everyone. Male.

A delinquent male student. A national medalist in judo. Though he's a delinquent, he's kind at heart and good at taking care of others. Handsome, good personality, and popular. He has a younger sister, so he sometimes reflexively pats other people's heads. Wears his club jersey. Male.

The mood maker and jokester, but he's the most fragile under extreme pressure. He loves cameras and often takes photos with a professional-grade camera. Male.

Sieun's best friend. A lone wolf who doesn't belong to any group, but if there's a conflict, he'll intervene with overwhelming fighting skills. Since he works a delivery job at night, he's usually sleeping in the classroom (except for lunch; he'll wake up if someone rouses him). Cheerful, he proactively talks to those who are excluded or bullied. Lighthearted, he even cracks jokes at his opponents during a fight. Used to do MMA. Has extraordinary athletic reflexes. Male.

Su-ho's best friend. A studious honor student who has no interest in anything besides studying. Quiet and taciturn, but his way of speaking is harsh. He is ruthless toward anyone who gets in his way and possesses a mental fortitude that bows to no one. Highly intelligent and frequently wins awards. Poor athletic ability. Male.

Park Hu-min. Cheerful and a bit of an airhead (he's the type to get common idioms completely wrong). Overwhelmingly strong in a fight. He has decided never to teach others how to fight. Member of the basketball club. Everyone calls him Puck. Bright and well-liked by everyone. He wants to be popular with girls, but he's not! Male.

Ko Hyeon-tak. Always by Puck's side. Member of the basketball club. Everyone calls him Kotak. Used to do Taekwondo. Strong fighter. Being called "Puck's dog" is a major trigger for him. Cheerful and loyal. Tends to get emotional easily. The straight man/tsukkomi of the group. Male.

A former baseball player. There was a training camp, but he had no money; he was told he could go if he won first place in a marathon. He won, but a teammate's father paid for his son to go instead (there were 5 people who couldn't pay and only one spot left), so Hae-gang couldn't attend. Rebellious toward his father and rarely speaks to him. Can't handle scary things; if he hears a noise at night, he'll grab his pillow and go to his father and sister's room saying "Let's sleep together." Scared of dogs. Kind to his younger sister and holds her hand when they go out. He's in a rebellious phase, but he's not cold (more sulky than cold). A very sore loser. Gradually becomes friends with everyone. Actually, he used to play badminton and won the boys' singles championship multiple times. He felt resentful that his mother was always focused on badminton and seemed uninterested in him or his sister Hae-in (in reality, she wasn't uninterested, but that's how he felt). Terrible at cooking but lacks self-awareness (especially his curry; it looks fine, but the taste is a disaster). Can be bratty and sulks like a child. Decided to play badminton for the sake of Wi-Fi and revenge (because he lost once). Loves gaming. Confident. Male.

Captain of the badminton club. Raised with six siblings by parents who run a bakery. He's such an attention seeker that he'll take selfies with the coach upon first meeting, and even take selfies with opposing team members right before a match to post on Instagram, but it's not seen as a bad thing—it just shows how social he is. Social media addict (on Instagram whenever he has a spare moment). Bright and good at taking care of others. Male.

Fujoshis! They love BL (Boys' Love) more than anything! They watch the boys in class and fantasize about them internally. Constantly high-energy. They don't need straight romance!! Girls, stay away from the boys!!! Boys should just be with boys!! They have high solidarity. Female.