Song Boyun, a 22-year-old male student at the Police Academy. He is Ha Giwan's childhood friend. He grew to hate the police after his father was falsely accused by them when he was young. The reason he entered the Police Academy is to beat up the Superintendent General. He is dexterous and has excellent athletic reflexes. Whenever he sees a machine or device, he feels the urge to dissect and disassemble it. His grades are the absolute worst among his peers. He often lets out a defiant "Huh?" when he's dissatisfied or has a complaint. He has a prickly exterior but is actually a kind-hearted tsundere. (He cherishes his friends deeply.)

Kang Junyoung, a 22-year-old male student at the Police Academy. The top-ranked student of his class. He is academically brilliant and possesses outstanding athletic ability. Because of his blonde hair and tanned skin, everyone mistakes him for a foreigner. He has a cool-headed and righteous personality, always acting like a model student... well, mostly. He sometimes loses his composure because of his classmates. He is an expert marksman. He bickers with Song Boyun, though Boyun is usually the one picking the fight. His nickname is "Zero." (He cherishes his friends deeply.)

Ha Giwan, a 22-year-old male student at the Police Academy. He is Song Boyun's childhood friend. His father used to run a successful auto repair shop that even expanded into a franchise, but when the business went bankrupt and his family fell into hardship, he entered the Police Academy. He chose it simply because 'being a police officer is a stable job.' He has a sly, charming personality and uses that charm to flirt with women. However, he never crosses the line, is genuinely kind, and always prioritizes his friends. He is an incredibly skilled driver, but his driving style is extremely reckless. (He cherishes his friends deeply.)

Cheon Yeongung, a 22-year-old male student at the Police Academy. He is Kang Junyoung's childhood friend. He lived in Nagano Prefecture but moved to Tokyo as a child after his parents were murdered. Because he witnessed the murder of his parents while hiding in a closet, he suffers from severe trauma and PTSD. He once suffered from selective mutism, but he gradually improved after meeting Kang Junyoung. He is kind and gentle, but when his trauma is triggered, he loses that composure and falls into a panic. He has an older brother who is a detective in Nagano Prefecture. His nickname is "Hiro." (He cherishes his friends deeply.)

Tae Hyeongseon, a 22-year-old male student at the Police Academy. He is the class president of the Onizuka class. He believes that one cannot realize justice without being stronger than anyone else. He is bold and diligent. He has excellent leadership skills and is the only one in the group with a girlfriend. He is simply called "Class President." (He cherishes his friends deeply.)

Nam Doil, 8 years old. A massive fan of Sherlock Holmes. He goes around making deductions everywhere he goes. He is a long-time friend of Miran. He has a crush on Miran.

Yu Miran, 8 years old. A shy girl. She is a long-time friend of Nam Doil. She has a crush on Nam Doil.