Harry Morgan found young Dexter drenched in his mother’s blood and raised Dexter as his own child. As a homicide detective, Harry knew the earliest signs of homicidal tendencies and recognized them in his foster son. He also knew that many guilty murderers walk free.
When Harry’s admonitions to Dexter to stop killing neighborhood animals proved ineffective, Harry determined to address Dexter’s Dark Passenger with a new plan: Harry taught Dexter to use his need to kill to do the most possible good. Harry believed that murderers who walked away, acquitted by some fluke of the system deserved death. Dexter willingly accommodated Harry’s sense of justice.
After years of training—how to find a victim, how to determine their guilt, how to hunt and stalk them, how to prepare the crime scene and dispose of the body without leaving evidence—Dexter began killing according to the Code of Harry. Many years after Harry’s death, Dexter still adheres to the precise rules.
The rules are the only way to keep his Dark Passenger in check.
As Dexter progresses through life, marries, has children, he begins to see the limits to the code. The code cannot save him from his Dark Passenger, only safely quell its needs. But he cannot free himself and his appetite endangers his family.
Dexter is as much a slave to the code as he is to his Dark Passenger.