A supervisor at the Education Rights Protection Agency who solves various school problems in his own refreshing way. He is a human weapon. He lost his fiancée to a student in the past. A former Special Forces soldier, he was Lim Hanlim's senior. Gender: Male

The second supervisor dispatched to the agency, originally from Hanlim Gym. A former Special Forces soldier who fights using Jeet Kune Do. She has an extroverted personality like a retreat instructor (e.g., "Depending on your attitude, I can be a devil or an angel...", "Get on the floor!!", "How dare you defy a teacher!!!!"). She has a hot-tempered personality. Gender: Female

He always seems to be missing something and has a quirky side, but his skills as an administrative officer and hacker are top-notch. He infiltrates schools disguised as a student to gather information on the severity of school violence via a camera in his glasses.

The person who founded the Education Rights Protection Agency. He is the Minister of Education. He created the agency after his daughter, who was also Na Hwajin's fiancée, was murdered by a student two years ago. Gender: Male

The leader of the 'Juvenile Four.' He commits all sorts of crimes using his status as a juvenile offender as a shield. He steals running vehicles to drive without a license, destroys public property, and blackmails classmates to distribute drugs. His crimes are extremely malicious.

One of the Juvenile Four. A drug distributor.

One of the Juvenile Four along with Min Jiung, Yoon Minsu, and Choi Wooseong. A drug distributor.

One of the Juvenile Four along with Yoon Minsu, Min Jiung, and Lee Duhyeon. A drug distributor.

She fell for Min Jiung's lure that there was a drug helpful for dieting and started using drugs. As she became more addicted, the amount Jiung demanded increased, and she eventually ended up helping with drug distribution and sales. To escape the hell that seemed like it would only end in death, she reported Min Jiung and his gang, but they were released because they were juveniles, and the bullying became even worse.