Hall , a forensic technician specializing in bloodstain pattern analysis for the fictional Miami Metro Police Department , who leads a secret parallel life as a vigilante serial killer , hunting down murderers who have not been adequately punished by the justice system due to corruption or legal technicalities.
Dexter "Dex" Morgan is the titular protagonist and narrator of the series. Dexter is a forensics expert and blood spatter analyst employed by the Miami Metro Police Department, but has a double life as a vigilante serial killer. As young boys, he and his older brother Brian witnessed the murder of their mother, Laura Moser and were left for two days in a shipping container filled with blood.
The incident left them psychologically scarred. Soon afterwards, Dexter was adopted by Harry Morgan , who hoped to help repress his memory of the death of his mother. He soon realized that Dexter had an insatiable urge to kill that would begin to intensify. Harry, frustrated with the number of people who avoided justice, decided to train Dexter as a killer who would target and dispatch other murderers. Dexter considers himself emotionally divorced from the rest of humanity; in his narration, he often refers to "humans" as if he is not one of them.
He makes frequent references to an internal feeling of emptiness, leading to several attempts in his youth to "feel alive". He claims to have no feelings or conscience and that all of his emotional responses are part of a well-rehearsed act to conceal his true nature. In the Season 1 of the television series, he had no interest in romance or sex; this changed when he became involved with Lila in Season 2.
He initially considered his relationship with Rita to be part of his disguise; however, by the end of the Season 4 , Dexter had fully evolved into a family man and wished to rid himself of his self-titled "Dark Passenger".
