Dying to know more about 'Dexter'

"Dexter" is about as good as evil can get. The Showtime series' titular character is a sociopath who is driven to kill. His adoptive father, Harry, a cop, taught him to channel his blood lust so that he only murders other murderers. In following his father's honor code, Michael C. Hall's Dexter fashions a type of life for himself while hiding slides of each victim's blood in his apartment's air-conditioning unit as trophies. Unsurprisingly, he's great at his day job as a blood spatter analyst for the Miami Police Department, where his adoptive sister Debra (Jennifer Carpenter) follows in their father's footsteps, just a little less bloodily. (Carpenter and Hall were married in December.)

Hall, previously known to audiences as David on HBO's "Six Feet Under," is indelible as a man possessed by darkness who tries very hard to resemble a normal human being. The Season 3 finale found him murdering his new best friend, escaping from, framing and killing another serial killer, and getting married to Rita (Julie Benz), his pregnant girlfriend. To viewers, it was all pretty reasonable behavior. Compelling as well: In three seasons he's been nominated for three Golden Globes and an Emmy.

Two days into shooting Season 4, which will begin Sept. 27, Hall sat down to talk about his character's dark path. As he joked, "I feel like I'm Dexter's press secretary sometimes," he added a caveat: "I don't think Dexter's the most reliable narrator from time to -- time, and I may not be the most reliable press secretary."

Each season has had a strong overarching theme concerning Dexter's connection with the world and with his darkness. Can you run them down?

I think the preoccupation in the first season is "What happened to me"; the second is "Am I good or am I bad," and in the context of that he plays with the idea of rehabilitation. In the third, he comes to recognize a desire for human connection remains in him and is, in a way, fed by the connections that he's had to do away with.

Dexter's own evolution has been huge; do you think he might be developing a soul?

He's undoubtedly developed the ability to simulate human behavior in increasingly convincing ways. As far as questions of does he have a soul or not, I'm reluctant to come down either way because I think that's the fun of the show. I don't think it's for me to say.

"Dexter" has a surprising amount of humor, and Dexter's often the straight man, observing everyone else's bizarre behavior.