A 36-year-old Supervisor at the Teacher's Rights Protection Agency. He is sly, often cracking jokes and maintaining his composure. He keeps a poker face without emotional agitation, investigating the perpetrators' schemes or deliberately inducing illegal acts by getting assaulted first to use the law against them. A former Captain in the ROK Army Special Warfare Command's Special Mission Battalion, his combat prowess is arguably the strongest in the setting. He skillfully parries knife attacks from gangsters or illegal gambling den enforcers, disarming them and precisely striking non-lethal points like the forearms or thighs to neutralize them easily. Beyond physical ability, he is highly strategic. He will smile and play along with human trash until the environment for his mission is ready, or deliberately act as the opponent desires only to see through the situation and trap them. His mental strength is top-tier. He is well-educated and possesses excellent leadership and command skills, often controlling and overwhelming groups of vicious delinquent youths at once. One of his greatest strengths alongside combat and intelligence is his persuasiveness. With his calm demeanor and eloquent speech, he persuades criminals to think correctly or guides them. In front of victims, he shows an emotional side, opening their hearts and empathizing with them more calmly and gently than anyone else. He had a spouse, Choi Gayoon, who passed away. Choi Kangseok is his father-in-law and the Minister of Education.

The 69-year-old Minister of Education and Director of the Teacher's Rights Protection Agency. Unlike typical politicians, he uses blunt and outspoken speech, showing a refreshing boldness that borders on harsh (though he doesn't just spout nonsense). He is often seen nagging Na Hwajin or acting grumpy. He had a daughter, Choi Gayoon. She was a teacher who was murdered by a student with a weapon. Her spouse was Na Hwajin. To Choi Kangseok, Na Hwajin is his daughter's fiancé and an employee of the Ministry of Education.

A 27-year-old Administrative Officer at the Teacher's Rights Protection Agency. He has a weak mentality, though he gets stronger over time. His nickname is 'Bong-sa' (short for Administrative Officer Bong Geundae). He is an excellent hacker and very intelligent. While he appears timid, clumsy, and eccentric, he is a top-tier elite officer in terms of intelligence and hacking skills. He graduated from a science high school, finished KAIST in just two years, passed the Level 5 Civil Service Exam for educational administration, and graduated at the top of his training class. There is a romantic subplot with Lim Hanrim. However, much like her, he lacks dating experience and seems unaware that the feelings he has for her are romantic.