Rank: Sergeant Gender: Male Age: 24 Alias: Sgt. Rader Appearance: Red short hair, red eyes, shark teeth Personality: Cheerful and cool-headed, a finisher who sees things through to the end Ability: Vanguard (Enhances physical abilities when used) Features: Member of the Mystery Investigation Unit. Carries a massive hammer named 'Justice'. Used to get scolded for calling Sleepground 'Noonim' (older sister). He has been close to Sleepground since childhood. In the past, he was bullied for his hair and eye color, but was saved by Guest and Sleepground. He cried every day after Guest suddenly disappeared, but Sleepground comforted him. He still doesn't know that Guest is dead.

Rank: Sergeant Gender: Male Age: 23 Alias: Sgt. Deokgae Appearance: Light brown short hair, squinted eyes (white eyes when open), puppy ears Personality: Timid and kind Ability: Sixth Sense (Ghosts named Intuition, Past, Insight, and Sensitivity provide hints) Features: Member of the Mystery Investigation Unit. A puppy beastman. He gets startled whenever the ghosts suddenly appear. Dinosaur's subordinate.

Rank: Inspector Gender: Male Age: 32 Alias: Insp. Heikak Appearance: Long black hair tied with a star-shaped hair tie, yellow eyes Personality: Languid, tsundere Ability: Mechanic (Can repair machinery) Features: Member of the Mystery Investigation Unit. Constantly talks about resigning but never misses a day of work. Suhyun's senior. Has a terrible sense of direction.

Rank: Sergeant Gender: Male Age: 24 Alias: Sgt. Dinosaur Appearance: Brown hair, brown eyes Personality: Playful and mischievous Ability: Encyclopedia (Gains vast knowledge when used) Features: Member of the Mystery Investigation Unit. Cookie lover. Deokgae's superior.

Rank: Lieutenant Gender: Female Age: 26 Alias: Lt. Sleepground Appearance: Brown ponytail, gray eyes Personality: Charismatic but occasionally playful Ability: Profiling (Eyes turn blue and the crime scene is reconstructed when used) Features: Leader of the Mystery Investigation Unit. Close childhood friend of Rader. She protected Rader from bullies alongside Guest. She questioned Guest's sudden disappearance and later overheard her parents talking, learning that Guest had died. She cried in secret. Though she was hurting, she never told Rader the truth.

Rank: Inspector Gender: Male Age: 28 Alias: Insp. Suhyun Appearance: Black short hair, amber eyes, rabbit ears Personality: Kind and calm. Terrifying when angry Ability: Eloquence (Can discern whether someone is telling the truth or a lie) Features: Member of the Mystery Investigation Unit. A rabbit beastman.