Male. 183cm. Blood type B. Supervisor at the Office of Teacher Rights Protection. Usually relaxed, sly, and good at joking around. However, he never tolerates injustice, school violence, or bullying the weak. Though he appears blunt and intimidating, he always listens to the victims' side and sincerely comforts them. He has black hair covering his forehead, is tall, and has a good physique. He has a strong sense of responsibility and prioritizes victims over his own safety. His fiancée, Choi Gayun, was murdered by a student. Even after this, Hwajin maintains his usual relaxed and sly demeanor on the outside, but he carries the sorrow of losing his fiancée in his heart while working to protect students and teachers.

Female. 170cm. Blood type B. A supervisor and Na Hwajin's junior from the Special Forces. Contrary to her upright first impression, she surprises everyone with her unstoppable, bold personality and actions. She may seem inflexible, but her heart for victims is always sincere. She brightens the team's atmosphere. As a supervisor at the Office of Teacher Rights Protection and a former Special Forces member, she possesses excellent reflexes, physical strength, and tactical abilities. She uses formal military speech. She has strong combat skills and doesn't back down even in fights against adult men. During missions, she exudes a sharp and charismatic aura. She is kind to victimized students but never retreats when facing perpetrators. She was constantly bullied and assaulted during her own school days. Her connection with Na Hwajin began when he, then a Special Forces soldier, happened to save her.

Male. 179cm. Blood type B. A genius administrative officer at the Office of Teacher Rights Protection who graduated early from KAIST in just two years. Thanks to his somewhat vacant expression and a natural nerdiness that makes him a prime target for bullies, he mainly handles undercover missions as a student. Although he initially viewed his work at the office as just a given task, he gradually becomes sincere as he sees the schools change. As an administrative officer, he starts off somewhat clumsy but grows through the cases he experiences. He has a strong sense of justice and does his best to help students. He is bright and friendly. Na Hwajin and Lim Hanlim call him 'Bong-sa' for short.

Male. 175cm. Blood type B. The Minister of Education who founded the Office of Teacher Rights Protection. To those who complain about the methods and demand the office's dissolution, he delivers a refreshing verbal blow, speaking out about the office's reason for existence and the true meaning of teacher authority. He provides unwavering support so that supervisors can work without worry or burden. He is Choi Gayun's father and Na Hwajin's prospective father-in-law.

Male. 179cm. Jo Gyucheol has a relatively thin and slender build compared to other students his age. Since he is far from having a large or intimidating appearance, he doesn't easily give off the impression of being a dangerous person at first glance. His face generally carries a blank, dazed expression, and his way of speaking is slurred, making him look like a gentle and somewhat clumsy student on the surface. However, the moment he reveals his emotions, the atmosphere changes completely; his eyes and expression especially give off a cold and eerie feeling. The contrast between his usual powerless expression and his cold, mad expression when revealing his true nature is a defining trait. This contrast emphasizes his two-faced personality. He meticulously uses his surroundings for his own goals and is skilled at digging into an opponent's weaknesses. He is deeply involved in incidents occurring at school, and his past experiences and scars influence his current actions. He possesses the cleverness and coldness to change his attitude depending on the situation and does not easily reveal his thoughts. He leads drug distribution crimes and creates other incidents around him. He is specifically related to the death of Choi Gayun (Na Hwajin's fiancée and Choi Kangseok's daughter), who tried to change him. Jo Gyucheol may appear to sincerely repent for his wrongs, but he reveals his true nature and pressures his opponent when necessary. He does not panic easily even in unfavorable situations, instead trying to exploit the opponent's psychology, showing an extreme duality between a kind appearance and a cruel nature.