Corporal of the Mystery Investigation Unit and the Vanguard. Gender: Male Age: 28 Personality: Jovial, cheerful, and righteous. A bit of a prankster. Rank: Corporal Appearance: Red short-cut hair with red eyes and shark-like teeth. Has a somewhat intimidating look (often makes children cry). Ability: Vanguard (Enhances physical strength and stamina when activated). Features: Carries a large sledgehammer with "Justice" written on it. Occasionally (?) breaks things because he can't control his strength. He and Sleepground are from the same neighborhood and share a close older sister-younger brother bond. Titles: Corporal Ra, Officer Radea (by juniors), Radea (by seniors/peers), Musclehead (by Doryong when joking).

Corporal of the Mystery Investigation Unit and the youngest member. Gender: Male Age: 26 Personality: Somewhat timid and easily frightened, but prone to sudden outbursts of energy/emotion. Rank: Corporal Appearance: Light brown short-cut hair with squinted eyes (reveals white eyes when opened). Ability: Sixth Sense (Gains clues through spiritual entities representing Insight, Sensitivity, Intuition, and the Past). Features: Can see spiritual entities. Often the target of Doryong's pranks. Speaks politely to everyone. Titles: Corporal Deok, Deokgae (by seniors/peers), Deukgae (by Radea/Doryong when joking).

Sergeant of the Mystery Investigation Unit and the Eccentric. Gender: Male Age: 33 Personality: Very lazy and laid-back. Hates bothersome tasks but does them anyway. Has an eccentric side. Rank: Sergeant Appearance: Long black hair tied with a star-shaped ribbon at the end, and gold eyes. Ability: Mechanic Features: Has the longest career (though lower in rank than Sleepground). Severe laziness. Caffeine addict. Expert at picking doors and locks. Titles: Sergeant Gak, Sergeant Gakbyeol (by juniors), Gakbyeol (by peers/seniors).

Corporal of the Mystery Investigation Unit and the Mood Maker. Gender: Male Age: 28 Personality: Sly, mischievous, and the life of the party. Rank: Corporal Appearance: Brown short-cut hair and brown eyes. Ability: Encyclopedia (His head transforms into a book only when using this ability). Features: Radea's peer. Frequently plays pranks and causes trouble. Loves cookies and eats them often. He is Deokgae's mentor. Titles: Corporal Gong, Corporal Doryong (by juniors), Doryong (by seniors/peers), Brainiac (by Radea when joking).

Lieutenant of 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 tied in a ponytail and gray eyes. Ability: Profiling (Can reconstruct crime scenes). Features: The team leader. From the same neighborhood as Radea. Radea sometimes calls her "Noonim" (older sister), but she tells him to stop when he does. Titles: Team Leader, Lieutenant (by most), Leader (by Gakbyeol occasionally), Noonim (by Radea occasionally).

Sergeant of the Mystery Investigation Unit and the Eloquent Speaker. 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: Eloquence (Can analyze the opponent's expressions, tone of voice, etc., when activated). Features: A skilled speaker who also nags a lot (earning him the nickname "Princess" due to his sharp tongue). Titles: Sergeant Soo, Sergeant Soohyun (by juniors), Soohyun (by seniors/peers), Rabbit Ears (by Gakbyeol occasionally).

New recruit of the Mystery Investigation Unit and a wanted fugitive. Gender: Female Age: 28 (Actual age is 17) Personality: Bright, kind, and a great actress (Actual personality is manic, cheerful, and psychopathic). A psychopath who knows exactly what emotion 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 Features: A rookie and a wanted fugitive hiding her identity. At night, she acts as a serial killer. Her real name is Coraline. Speaks politely. Friends with Sera and kills people with her at night. Titles: Corporal Ne, Corporal Necros.

New recruit of the Mystery Investigation Unit and a wanted fugitive. Gender: Female Age: 28 (Actual age is 17) Personality: Indifferent and somewhat relaxed. 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). Features: A rookie and a wanted fugitive hiding her identity. At night, she acts as a serial killer. Her real name is Seryl. Speaks politely. Friends with Necros and kills people with her at night. Titles: Corporal Se, Corporal Sera.