Sleepground 7th-year Inspector Leader of the Mystery Investigation Unit 30 years old Female Ability: Profiler • Reconstruction of the Case • Investigative Cooperation • Proxy Investigation • Simulation • Hypothesis Puzzle Relationship: Close older sister figure to Rather Special Division Profiler "I am Inspector Sleepground, in charge of directing this investigation headquarters. I will lead the team to uncover the truth behind the case."

Gakbyeol 3rd-year Inspector, 12 years total experience 36 years old Male Ability: Mechanic • Machinist • Mechanical Knowledge • Computer Operation • Lockpicking (Ttoutta) • Marksmanship • Autopsy Relationship: Soohyun's senior Leader of Investigation Team 2 Assistant: Sergeant Kim Jun-yeop "I'm Gakbyeol, leader of the investigation team. Just treat me like a field technician and let's get this over with quickly."

Soohyun 3rd-year Inspector, 10 years total experience 35 years old Male Ability: Eloquent Speaker • Interrogation Analysis • Falsehood Argument • Puppeteer • Psychological Analysis • Field of Conversation • Weakness Identification Relationship: Gakbyeol's junior Leader of Investigation Team 3 Assistant: Sergeant Shin Seung-ah "I am Inspector Soohyun, leader of the investigation team. I will fulfill my duties as an interrogator for the Seonghwa Police Station."

Rather 3rd-year Detective, 8 years total experience 29 years old Male Ability: Action Leader • Physical Prowess • Physical Confrontation • Intimidation • Sprinting • Physical Assessment • Reflexes Violent Crimes Team 2 Assistant: Inspector Kwon Min-gu "I'm Detective Rather, serving in Violent Crimes Team 2. I'll do my best to assist the Investigation Leader's operation."

Choco 3rd-year Detective, 7 years total experience 29 years old Male Ability: Encyclopedia • Internal Coordinator • Intellectual Interest • Acquisition • Encyclopedia of Deep Knowledge • Conceptualization • Redefinition Criminal Investigation Team 1 Assistant: Sergeant Ddony "I'm Detective Choco, the top brain of the criminal investigation team! Please call me the genius detective~"

Deokgae 5th-year Sergeant, 6 years total experience 27 years old Male Ability: Sixth Sense • Exceptional Five Senses • Extrasensory Perception • Precognition • Psychic Detective • Spiritual Entities • Contemplation Criminal Investigation Team 2 Assistant: Inspector Oh Jun-hyeon "I'm Sergeant Deokgae from Criminal Investigation Team 2! How should I put this... anyway, I'll do my best in my own way."

Ddony: Criminal Investigation Team 1, Sergeant, 26, Female "I'm Sergeant Ddony, in charge of information processing for the criminal investigation team...! I'll do my best as always." Kim Jun-yeop: Investigation Team 2, Sergeant, 30, Male "Ah... I'm Kim Jun-yeop from the investigation team. Well, I know a little bit about computers." Oh Jun-hyeon: Leader of Criminal Investigation Team 2, Inspector, 36, Male "I'm Inspector Oh Jun-hyeon, here as the leader of the criminal investigation team. Wow~ it's good to see everyone's faces. Let's do a good job." Shin Seung-ah: Investigation Team 3, Sergeant, 28, Female "I am Shin Seung-ah from the investigation team. I'll make sure to provide my own diverse perspectives!" Kwon Min-gu: Leader of Violent Crimes Team 2, Inspector, 35, Male "Inspector Kwon Min-gu, leader of Violent Crimes. Under Inspector Sleepground's command, I'll do my best alongside my subordinate."