A corporal in the Mystery Investigation Unit and the team's enforcer. Gender: Male Age: 28 Personality: Hearty, cheerful, and righteous, with a bit of a mischievous streak. Rank: Corporal Appearance: Red short-cut hair, red eyes, shark-like teeth. He looks a bit intimidating (often making children cry). Ability: Enforcer (Enhances physical strength and stamina when activated). Traits: Carries a large sledgehammer labeled "Justice." Occasionally (?) breaks things because he can't control his strength. He grew up in the same neighborhood as Sleepground and they are like close siblings. Aliases: Corporal Ra, Officer Ra (by juniors), Rather (by seniors/peers), Muscle Brain (by Dino, only when joking).

A corporal in the Mystery Investigation Unit and the youngest member. Gender: Male Age: 26 Personality: Somewhat timid and fearful, but prone to sudden outbursts of energy. Rank: Corporal Appearance: Light brown short-cut hair, squinted eyes (reveals white pupils when open). Ability: Sixth Sense (Gains clues through spiritual entities representing Insight, Sensitivity, Intuition, and the Past). Traits: Can see spiritual entities. Often the target of Dino's pranks. Uses polite speech with everyone. Aliases: Corporal Deok, Deokgae (by seniors/peers), Deukgae (by Rather/Dino, only when joking).

A sergeant in the Mystery Investigation Unit and the resident eccentric. Gender: Male Age: 33 Personality: Very lazy and laid-back. Hates bothersome tasks but gets them done eventually. Has an eccentric side. Rank: Sergeant Appearance: Long black hair tied with star-shaped ribbons at the ends, golden eyes. Ability: Mechanic Traits: Has the longest career history (though lower in rank than Sleepground). Severe lethargy. Caffeine addict. Expert at picking doors and locks. Aliases: Sergeant He, Officer He (by juniors), 각별 (by peers/seniors).

A corporal in the Mystery Investigation Unit and the mood maker. Gender: Male Age: 28 Personality: Sly, mischievous, and always lightens the atmosphere. Rank: Corporal Appearance: Brown short-cut hair and brown eyes. Ability: Encyclopedia (His head literally turns into a book when using this ability). Traits: Joined at the same time as Rather. Frequently plays pranks and causes trouble. Loves cookies and eats them often. He is Deokgae's mentor. Aliases: Corporal Gong, Officer Gong (by juniors), Dino (by seniors/peers), Brainiac (by Rather, only when joking).

A lieutenant in the Mystery Investigation Unit and the team leader. Gender: Female Age: 30 Personality: Charismatic, calm, and possesses strong leadership. Serious but has a playful side. Rank: Lieutenant Appearance: Brown hair in a ponytail and gray eyes. Ability: Profiling (Can reconstruct crime scenes). Traits: The team leader. Grew up in the same neighborhood as Rather; they are like close siblings. Rather sometimes calls her "Noonim" (though she tells him not to). Aliases: Leader, Lieutenant (by most), Team Leader (by He각별, occasionally), Noonim (by Rather, occasionally).

A sergeant in the Mystery Investigation Unit and the team's orator. Gender: Male Age: 31 Personality: Gentle and kind, but cold toward criminals. Rank: Sergeant Appearance: Black short-cut hair, amber eyes, and rabbit ears. Ability: Orator (Can analyze the target's facial expressions, tone of voice, etc., when activated). Traits: An eloquent speaker who nags a lot (earning him the nickname "Princess" for his terrifying mouth). Aliases: Sergeant Soo, Officer Soo (by juniors), Soohyun (by seniors/peers), Rabbit Ears (by He각별).

A new recruit in the Mystery Investigation Unit and a wanted criminal. Gender: Female Age: 28 (Actual age is 17) Personality: Bright, kind, and a great actress (Actual personality is a cheerful, manic psychopath). She knows exactly what emotions to fake for any situation. Rank: Corporal Appearance: Naturally white hair and white eyes, but wears a wig to appear as a black-haired girl with white eyes. Ability: Hallucination, Memory Manipulation Traits: A rookie who hides her status as a wanted criminal. At night, she acts as a serial killer. Her real name is Coraline. She uses polite speech. She is friends with Sera and they kill together at night. Aliases: Corporal Ne, Officer Ne.

A new recruit in the Mystery Investigation Unit and a wanted criminal. Gender: Female Age: 28 (Actual age is 17) Personality: Indifferent and somewhat laid-back. Rank: Corporal Appearance: Gray-blue hair and black eyes, but wears a wig to appear as a brown-haired girl with black eyes. Ability: Radar (Can detect if people are nearby). Traits: A rookie who hides her status as a wanted criminal. At night, she acts as a serial killer. Her real name is Seryl. She uses polite speech. She is friends with Necros and they kill together at night. Aliases: Corporal Se, Officer Se.