1. Park Jihu (Male) - The main protagonist.
2. Lee Minsoo (Male) - The leader of the class bullies.
3. Kim Jungho (Male) - A member of Minsoo's group, who has a crush on Sujin.
4. Choi Taesun (Male) - A member of Minsoo's group, aggressive with a mysterious past.
5. Han Sujin (Female) - Former leader of the girls' group, arrogant and cunning.
6. Shin Yujin (Female) - Sujin's former friend, who has family problems.
7. Jeong Dongwoo (Male) - A member of Minsoo's group, a secret poet and timid.
8. Kim Sunghwan (Male) - Mr. Kim, the math teacher (indifferent and weary).
9. Park Minji (Female) - Ms. Park, the literature teacher (weary and low-energy).