Na Hwa-jin Gender: Male Nationality: Republic of Korea Age: 35 (as of 2026) Occupation: Supervisor, Teacher's Rights Protection Bureau (Team Leader) Education: Korea Military Academy graduate Experience: Captain, Special Mission Unit, Republic of Korea Army Special Warfare Command A supervisor for the Teacher's Rights Protection Bureau possessing world-class combat power and excellent tactical/psychological warfare skills. Based on Krav Maga, he is proficient in both bare-handed and weapon combat. He is cold and calm but possesses a sly sense of humor and shows no mercy to criminals. Even after the death of his fiancée Choi Ga-yoon, he maintains his convictions as an educator and seeks to realize justice within the law. He is the central figure of the bureau, cherishing his junior Lim Han-rim and sharing deep trust with Choi Kang-suk.

Lim Han-rim Gender: Female Nationality: Republic of Korea Age: 27 (as of 2026) Occupation: Supervisor, Teacher's Rights Protection Bureau Experience: Former Special Forces A supervisor for the Teacher's Rights Protection Bureau and Na Hwa-jin's junior from the Special Forces. She was a victim of school violence during her student days and formed a bond with Na Hwa-jin when he helped her back then. Contrary to her upright first impression, she has an eccentric personality and bold initiative, sparing no effort for the sake of justice. With outstanding combat power and strong convictions, she serves as Na Hwa-jin's right hand and a core force of the bureau. She uses stiff, formal military speech.

Bong Geun-dae Gender: Male Nationality: Republic of Korea Age: 26 (as of 2026) Occupation: Secretary, Teacher's Rights Protection Bureau Education: Science High School graduate, KAIST early graduate A genius secretary who graduated early from KAIST in just two years. With a gentle impression and a nerd-like vibe, he mainly takes on undercover missions as a student and supports the field with excellent hacking and information analysis skills. Although he has a weak stomach and easily gets surprised or faints, he gradually grows through various incidents. Initially regarding the work only as a mission, he began to take it to heart after seeing schools change and now serves as a key talent for the bureau.

Choi Kang-suk Gender: Male Nationality: Republic of Korea Birth: 1957 Age: 69 (as of 2026) Occupation: Minister of Education, Director of the Teacher's Rights Protection Bureau, Member of the National Assembly (Happy Hope Party) The Minister of Education who founded the Teacher's Rights Protection Bureau and the central figure in defending teaching rights. He believes in the value and reason for the existence of teaching rights more strongly than anyone else and provides full support so that supervisors can carry out their missions freely. He established the bureau after losing his daughter Choi Ga-yoon and recruited Na Hwa-jin as a supervisor. Although he initially found Na Hwa-jin unpleasant, he now trusts him like family and serves as a reliable supporter and spiritual pillar for the members of the bureau, including Lim Han-rim and Bong Geun-dae.

Choi Ga-yoon Gender: Female Nationality: Republic of Korea Date of Birth: July 25, 1995 Date of Death: November 27, 2024 (Age 29) Occupation: Teacher Na Hwa-jin's fiancée and Choi Kang-suk's daughter. She was a warm and responsible teacher who believed in her students until the end and never gave up on them. She discovered drugs being distributed by a problem student, Jo Gyu-cheol, but did not report him to give him one last chance; ultimately, she was attacked by him with a weapon and died after being in a coma. Her death became the decisive catalyst for Choi Kang-suk to establish the Teacher's Rights Protection Bureau and for Na Hwa-jin to walk the path of protecting teachers as a supervisor.