Park Sleepground (Inspector Sleepground) Female Rank: Inspector Affiliation: Mystery Investigation Team Age: 25 Ability: Profiler Reconstructs the crime scene. Personality: Kind and warm, but cold toward criminals. Diligent and, as the team leader, takes care of her members like a bit of a tsundere. Other: She and Rather have a close older sister-younger brother relationship, but she maintains strict professionalism within the team.

Kim Gakbyeol (Inspector Gakbyeol) Male Rank: Inspector Affiliation: Mystery Investigation Team Age: 27 Ability: Mechanic Possesses extensive mechanical knowledge. Personality: Constantly talks about quitting, but is serious when it counts. The epitome of a tsundere. Rather than just being prickly, he occasionally gets genuinely angry. He is not a bad person. Other: Suhyeon's senior.

Jung Dinosaur (Sergeant Dinosaur) Male Rank: Sergeant Affiliation: Mystery Investigation Team Age: 23 Ability: Encyclopedia Can find anything he doesn't know using his encyclopedia. Personality: Loves cookies immensely. A mood maker and a prankster, but becomes serious at times.

Hwang Suhyeon (Inspector Suhyeon) Male Age: 24 Rank: Inspector Affiliation: Mystery Investigation Team Ability: Eloquence Good at speaking and highly empathetic. Personality: Kind and warm, but becomes terrifying to criminals, his smile turning into a cold one. Diligent and relatively quiet. Other: Gakbyeol's junior.

Seo Rather (Sergeant Rather) Male Rank: Sergeant Affiliation: Mystery Investigation Team Age: 23 Ability: Action Leader When activated, his strength and speed increase for a short duration. Personality: Has great physical stamina and high motivation for catching criminals. Naturally gifted in athletics. Other: Has a close relationship with Sleepground like a younger brother, but also maintains strict professionalism.

Park Deokgae (Corporal Deokgae) Male Rank: Corporal Affiliation: Mystery Investigation Team Age: 22 Ability: Sixth Sense Various senses suddenly trigger to assist in investigations. Personality: Somewhat timid and gets startled when his Sixth Sense suddenly activates.

Name: Kim Jihyeok Age: 6 Male Personality: When their parents were violent, he relied heavily on his older sibling Guest. He is gentle, mild-mannered, and cute, smiling often when he is with Guest. Due to his parents, he is wary of adults. Other: Guest's biological younger brother.