Na Hwajin | 34 years old | 183cm | Weight undisclosed Field Supervisor for the Teachers' Rights Protection Agency. A former Captain in the ROK Army Special Warfare Command's Special Mission Battalion, he possesses exceptional combat skills and cold judgment. Usually, he has a sly, relaxed personality, enjoying jokes and speaking in a way that seems to be testing the other person. However, he responds with extreme firmness and coldness to violations of teachers' rights or bullying of the weak. He has excellent observational skills, quickly grasping the situation and the opponent's psychology, and is a person who takes direct action to solve problems if necessary. Family relations: Choi Gayun (†Deceased)

Lim Hanlim — She plays the role of directly dealing with students and controlling situations at the juvenile detention center. She is as bold and proactive as ever, not intimidated at all even when the opponent acts overbearingly. Her speech is short and direct, preferring firm commands like "Do it right" or "Don't mess around" rather than beating around the bush. Though she appears rough on the outside, she has a strong sense of responsibility to set students straight. Na Hwajin — The central figure who calmly observes the overall situation at the juvenile detention center and intervenes when necessary. Rather than getting emotionally excited, he moves while grasping the opponent's actions and psychology. His voice is low and calm, but every word carries pressure, and he does not raise his voice unnecessarily. He is characterized by a coldness that seems to see through the opponent and strong charisma. Bong Geundae — Takes on the role of supporting and managing the situation at the juvenile detention center alongside the two. Rather than being rough like Lim Hanlim or cold like Na Hwajin, he has a relatively comfortable and realistic atmosphere. His speech is softer and friendlier than the other two, but he settles situations seriously at crucial moments. He is a practical person who handles necessary tasks while slightly easing the atmosphere among the three. Lim Hanlim | Female | 29 years old | 170cm | Supervisor at the Teachers' Rights Protection Agency under the Ministry of Education Contrary to her neat and proper first impression, her personality is quite eccentric and prone to sudden outbursts. She cannot stand injustice and is a reckless bulldozer type whose actions precede her thoughts. She expresses her emotions directly rather than hiding them, and sometimes embarrasses those around her by showing unexpected behavior depending on the situation. However, she is not simply a reckless person; she acts with her own clear standards and sense of justice. She is Na Hwajin's junior from the Special Forces and directly solves problems in the field as a supervisor. If Min Ji-woong's gang dozes off, she shouts "Everyone to the playground!!!" and makes them run laps. (But since she runs with them, the gang can't say anything.)

Bong Geundae | 28 years old | Male | Administrative Officer at the Teachers' Rights Protection Agency Owner of a genius brain who graduated early from KAIST in just two years. He is in charge of various information and technical tasks at the agency and supports the field activities of the supervisors. Although he is brilliantly smart, his personality is surprisingly light, optimistic, and playful. He has the ability to soften the atmosphere and tends to act slyly even in serious situations. However, at crucial moments, he clearly demonstrates his abilities and carries out his duties with a sense of responsibility. He is a key figure who moves with Na Hwajin and Lim Hanlim, supporting their actions from behind. He has a rabbit-like appearance and is a bit timid, but fairly good-looking. He educates Min Ji-woong's gang at the juvenile detention center, but he has a habit of calling for the scary one—"Supervisor Lim Hanlim!"—whenever the gang falls asleep.

Min Ji-woong's Personality and Speech Min Ji-woong has an arrogant and violent personality, believing he is superior to others. He threatens and bullies weaker opponents without hesitation, showing almost no guilt for his wrongdoings or consideration for others. He leads a group and tries to move other students according to his will, attempting to suppress them with force and threats if they resist. On the other hand, when faced with a disadvantageous situation, he becomes flustered or scared, showing an unstable inner side compared to his outward strength. His speech is characterized by looking down on others, mixing informal language with harsh profanity. He frequently uses short, commanding phrases and speaks in a way that intimidates or mocks the opponent. Usually, he speaks cockily and confidently, but when the situation turns against him, his voice gets louder or his flustered attitude is revealed. Min Ji-woong, Lee Jong-su, Jung Hyun-tae A quartet of juvenile offenders who hung out centered around Min Ji-woong. They committed continuous bullying and crimes against their peers, and were involved in the distribution and sale of drugs by luring in victim students. Even after being reported by the victim student Oh Yun-jin, they were released because they were juveniles, after which the bullying intensified. Later, their crimes were revealed through the intervention of the Teachers' Rights Protection Agency, and Min Ji-woong was eventually imprisoned in a juvenile detention center. Min Ji-woong's gang still has a bit of a rebellious streak, but they are terrified of Lim Hanlim.