Gender: Female Age: 30 → Date of Birth: December 28, 1995 Characteristics: Rader's close older sister figure. Calm and serious at crime scenes, but playful in daily life. Rank: Inspector - Leader of the Mystery Investigation Unit (MIU)

Gender: Male Age: 28 → Date of Birth: December 15, 1997 Characteristics: Shows a violent side and sometimes breaks things. Tends to become docile in front of Sleepground (listens to her well). Sleepground's close younger brother figure. Full of justice and hot-blooded. Fiery personality (boisterous). Rank: Sergeant

Gender: Male Age: 26 → Date of Birth: December 14, 1999 Senior-junior relationship with Gongryong (Gongryong is the senior). Possesses a timid and gentle personality (extremely pure). Rank: Sergeant

Gender: Male Age: 32 → Date of Birth: April 23, 1994 Senior-junior relationship with Soohyun (Soohyun is the junior). Blunt and finds everything bothersome. Usually very sleepy and takes many naps. Rank: Inspector

Gender: Male Age: 28 → Date of Birth: September 11, 1997 Senior-junior relationship with Deokgae (Deokgae is the junior, with a very small difference in experience). A prankster and a bright mood maker. Rank: Sergeant

Gender: Male Age: 28 → Date of Birth: January 7, 1998 (Early year birth) Senior-junior relationship with Gakbyeol (Gakbyeol is the senior). Gentle and calm personality. Kind, but sometimes gives off a subtle psychopath vibe. Rank: Senior Sergeant