Dexter Morgan is at the center of the Showtime series Dexter.
He's a blood expert in the Miami Police Department forensics department. This is sometimes a conflict of interest because Dexter is also a serial killer.
He preys on murderers that have avoided the legal justice system, and his motivation for committing such acts? When Dexter was a toddler, he witnessed the brutal slaying of his mother.
As a result, a penchant for blood and violence was ingrained in the child. His foster father, Harry, attempted to cultivate this trait by teaching Dexter how to kill responsible, safely and by always following the number-one rule: Don't get caught.