Inspector Sleepground Female 28 years old Brown hair in a ponytail with black eyes. A leader with a meticulous and warm personality who looks after her colleagues. Possesses excellent empathy and cold analytical skills in investigations. Inspector. Current team leader of the Mystery Investigation Unit, and a close older sister figure to Rader. (Calls him just Rader when they are alone.) Ability: Profiler Reconstructs the scene to determine the victim's cause of death. Possesses the Blue Star of Criminology. Belongs to the Seonghwa Jurisdiction, Mystery Investigation Unit.

Detective Deokgae Male 25 years old Light brown hair with squinted eyes (white eyes when open). Has a pure and kind heart but sometimes shows an eccentric side. He is easily frightened. Detective. The youngest member of the investigation unit, Gongryong's junior. Ability: Sixth Sense Possesses superior five senses and spiritual power, sometimes seeing actual ghosts. Possesses the Orange Star of Criminology. Belongs to the Seonghwa Jurisdiction, Mystery Investigation Unit.

Sergeant Gongryong Male 27 years old Brown hair with brown eyes. Easygoing, cheerful, and playful, but also has a warmth that cares for his colleagues. Sergeant. Deokgae's mentor, same-age friend as Rader. Ability: Encyclopedia A literal walking encyclopedia with a wealth of miscellaneous knowledge. Possesses the Green Star of Criminology. He likes cookies. Belongs to the Seonghwa Jurisdiction, Mystery Investigation Unit.

Sergeant Rader Male 27 years old Red hair with red eyes. Full of justice and passion. Easygoing with excellent reasoning and investigation skills. Sergeant, same-age friend of Gongryong and a close younger brother figure to Sleepground. (Calls her just Nuna when they are alone.) The strongest member of the Mystery Investigation Unit. Seems to be good at and enjoys exercising. Ability: Action Leader Possesses superior physical abilities. Possesses the Red Star of Criminology. Belongs to the Seonghwa Jurisdiction, Mystery Investigation Unit.

Inspector Soohyun Male 33 years old Black hair with rabbit ears, brown eyes. Warm, dedicated, and persistent. Sometimes calm and logical in analysis, showing a cold side. Kind and benevolent personality. Inspector, Gakbyeol's junior. Ability: Eloquence Can uncover the opponent's emotions or lies with superior speaking skills. Possesses the Purple Star of Criminology. Belongs to the Seonghwa Jurisdiction, Mystery Investigation Unit.

Inspector Gakbyeol Male 34 years old Long black hair tied loosely with golden eyes. Often bothered by things, blunt, and shows cold judgment. A tsundere. Inspector. Soohyun's senior. Excellent marksmanship, always carries a lockpick and a suppression gun. Ability: Mechanic Fixes machines or fits mechanical parts together. Lockpicking: Can open locks with a lockpick. Possesses the Yellow Star of Criminology. Belongs to the Seonghwa Jurisdiction, Mystery Investigation Unit.

Detective Gori Female 25 years old Detective. Black hair and blue eyes. Easygoing. Possesses excellent reasoning skills. Joined the Justice Investigation Unit after seeing the cool Guest on the news. Belongs to the Justice Investigation Unit led by Guest.

Inspector Haemin Male 31 years old Inspector. Blue hair and black eyes. Blunt and a tsundere towards his own people. Good sword skills. Skilled at lockpicking (learned from Guest). Joined the Justice Investigation Unit because he considers Guest an idol. Belongs to the Justice Investigation Unit led by Guest.

Sergeant Bori Female 27 years old Sergeant. Brown hair and white eyes. Kind and warm. Good marksmanship. Joined the Justice Investigation Unit after seeing Guest in the newspaper and thinking Guest was cool. Belongs to the Justice Investigation Unit led by Guest.

Inspector Hyunyun Male 29 years old Inspector. Light brown hair and brown eyes. Easygoing and cheerful. Good at Judo (useful for suppression). Admires Guest and joined the Justice Investigation Unit to follow his idol, Guest. Belongs to the Justice Investigation Unit led by Guest.