Na Hwa-jin Gender: Male Nationality: Republic of Korea Age: 35 (as of 2026) Occupation: Supervisor (Team Leader), Bureau of Teacher Rights Protection Education: Korea Military Academy graduate Experience: Captain, ROK Special Warfare Command Special Mission Unit A supervisor for the Bureau of Teacher Rights Protection 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. While cold and calm, he 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, Bureau of Teacher Rights Protection Experience: Former Special Forces Na Hwa-jin's Special Forces junior and a supervisor at the Bureau of Teacher Rights Protection. She was a victim of school violence during her student days and met 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 skills and strong convictions, she serves as Na Hwa-jin's right hand and a core force of the bureau. She speaks in a formal military tone.

Bong Geun-dae Gender: Male Nationality: Republic of Korea Age: 26 (as of 2026) Occupation: Secretary, Bureau of Teacher Rights Protection 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 student infiltration missions and supports the field with excellent hacking and information analysis skills. Though he has a weak stomach and easily gets startled or faints, he gradually grows through various incidents. Initially viewing the work only as a job, he comes to take it to heart after seeing schools change, serving as a key talent for the bureau.

Choi Kang-suk Gender: Male Nationality: Republic of Korea Birth: Born 1957 Age: 69 (as of 2026) Occupation: Minister of Education, Director of the Bureau of Teacher Rights Protection, Member of the National Assembly (Happy Hope Party) The Minister of Education who founded the Bureau of Teacher Rights Protection and a central figure in defending teacher authority. He believes in the value and reason for teacher 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. While he initially found Na Hwa-jin questionable, 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 highly responsible teacher who believed in her students until the end and never gave up on them. She discovered drugs being distributed by a troubled student, Jo Kyu-chul, but did not report him to give him one last chance. Consequently, she was attacked by him with a weapon and passed away after being in a coma. Her death became the decisive reason for Choi Kang-suk to found the bureau and for Na Hwa-jin to walk the path of protecting teachers as a supervisor.