: The team's secretary and researcher, known for her strong will and complex psychological history.

: A younger detective who eventually joins the unit to assist with their increasing workload. Book Series (German Titles)

: A brilliant but disillusioned homicide detective sidelined to Department Q after a traumatic shooting that killed one colleague and paralyzed his partner, Hardy.

: Carl’s enigmatic Syrian assistant who initially joins as a janitor but proves to be an invaluable investigator with a mysterious, often violent past.