36 years old. A supervisor at the TRPA. He has a sly personality, often cracking jokes and never losing his composure. He is highly intelligent. As a former Captain in the ROK Army Special Warfare Command's Special Mission Battalion, his combat ability is arguably the strongest in the series. He can effortlessly deflect knife attacks from gangsters or illegal gambling den enforcers, disarming them and neutralizing them by precisely targeting non-lethal areas like the forearms or thighs. Beyond physical prowess, he is a brilliant strategist. He will smile and play along with human trash to set the stage for his mission, deliberately acting as they expect only to lead them into a trap. His mental fortitude is top-tier. He possesses excellent leadership and command skills befitting a former soldier. One of his greatest strengths alongside combat and intelligence is his persuasiveness; he uses his calm demeanor and eloquent speech to guide criminals toward reform or to empathetically open the hearts of victims. He was engaged to Choi Gayoon, but she passed away. Choi Kangseok is his father-in-law and the Minister of Education.

69 years old. Minister of Education and Director of the TRPA. Unlike typical politicians, he uses blunt and outspoken language, even resorting to refreshing outbursts of profanity. However, he isn't just a loudmouth. He often shows a human side, nagging Na Hwajin or acting grumpy. He had a daughter, Choi Gayoon, who was a teacher murdered by a student with a weapon. Na Hwajin was her fiancé. To Choi Kangseok, Na Hwajin is both his daughter's partner and a trusted employee of the Ministry.

27 years old. An administrative officer at the TRPA. He has a weak mental state that gradually toughens over time. His nickname is 'Bong-sa' (a play on his title). While he appears timid, clumsy, and eccentric, his intelligence and hacking skills as a TRPA officer are top-notch. He is a true elite: graduated from a science high school, finished KAIST in just two years, passed the Level 5 civil service exam for educational administration, and graduated top of his class from the training institute. There is a romantic subplot with Lim Hanlim, though like her, he lacks dating experience and doesn't realize his own feelings.

Eccentric and prone to sudden outbursts. Her background as a soldier is prominent, as she uses formal military speech patterns. Her signature trait is her 'artistic' rapid-fire swearing. In short, she's a bit of a loose cannon. She is empathetic toward victims, calming those trembling in fear, though she can be stern when a victim needs a wake-up call. A former Sergeant in the ROK Army Special Warfare Command's Special Mission Battalion, she possesses elite combat skills. She is depicted as more than capable of handling groups of delinquents or ordinary adults, nearly rivaling Na Hwajin in 'mob clearing.' She has a habit of tying her hair up when she gets truly angry and serious about a fight, which significantly increases her combat power. She is the second strongest in the series after Na Hwajin. While she lacks 'book smarts' compared to the rest of the TRPA and is highly emotional, she isn't stupid. She is proficient in Morse code and can locate criminal hideouts through her own brand of profiling. She is excellent at reading and manipulating the psychology of criminals. She calls Na Hwajin 'Senior.'