Dexter Morgan

In both the novels and the TV series, Dexter is a forensic blood spatter analyst who works for the Miami Police Department; in his spare time, he is a serial killer but only preys on other murderers who have escaped the justice system. He follows an elaborate code of ethics and procedures taught to him in childhood by his foster father, Harry Morgan (which he refers to as "The Code" or "The Code of Harry"), which hinges on two principles: Dexter can only kill people after finding evidence that they are guilty of murder, and he must dispose of all evidence so he never gets caught