Diagnosing Dexter
Okay, enough, I can't really do that style for very long. I think one reason that Jeff Lindsay may be trying to end the series is because of the Purple Prose.
I am quite familiar with Dexter Morgan, at least the book version; I have only ever seen the first season of the TV show. Again and again, Dexter insists that he is a sociopath, that he doesn't have feelings like other people, and that this is why he is a serial killer. However, he shows in quite a few ways that, even in the earliest books, this is by no means the case. He does care about a few people, including his adopted sister Deborah and his girlfriend (later wife) Rita Bennett and her two children, Cody and Astor. And he cared a great deal for his adopted father, the sainted Harry, who put his feet on the "Harry Path," shaping Dexter into a serial killer who only kills other serial killers. A real sociopath would have cheerfully absorbed everything Harry Morgan could teach him...and then made Harry his first victim, or at least made very sure that he could never change his mind and betray Dexter. And a real sociopath would have happily killed Deborah, and then either run off with Brian or set him up for being killed in his turn.
So now we know what Dexter is not. But what is he? He gives us the answer, again and again, but most readers are so caught up in the story, they don't get it.
From the beginning of the books, Dexter talks to the reader about his "Dark Passenger," which takes over when he is about to commit another murder. The Dark Passenger is in control during his murders, and he is often aware of its presence in his mind, watching when he is investigating someone else's murder and often providing the insights that his sister values so highly. He speaks of it as though it is something separate from himself. And he's right.
What we have here, I believe, is a case of what was called, once, Multiple Personality Disorder. The main personality, "Dexter Morgan," is the guy who gets through a day at the police department, analyzes blood spray patterns to determine what happened, and goes home or to Rita's place. The secondary personality, the "Dark Passenger," is only interested in murder, and takes control of Dexter's body when he's about to kill someone.
The Dark Passenger is not a complete secondary personality; it has no name, and does not take an interest in activities other than murder. Unlike some sufferers from this disorder, Dexter can remember perfectly what happens when the Passenger is in control.
Dissociative Personality Disorder (the latest name for this, according to Wikipedia; hey, I'm no psychologist and have to use the sources I have) has been said to occur in people who suffer severe trauma very young. Dexter certainly qualifies, having been left with his brother in a shipping container with their mother's hacked-up body after their mother's attempt to double-cross her Colombian partners in a drug ring went very bad. Harry saved them, and while he adopted Dexter, his year-older brother Brian went on to foster care and a future as a serial killer in his own right.
I can't be sure of this diagnosis, but it fits what I read in the books. I may just write Jim Lindsay and ask him about it. (And yes, I am aware of the novel where the Passenger is portrayed as an outside entity of evil, but that was not referred to in later books and Lindsay may have decided it didn't work.)