Source: http://www.fanpop.com/clubs/dexter/images/34653339/title/dexter-season-8-ew-magazine-cast-photos-photo/3
The first season of "Dexter" was created on the grounds of a novel, titled "Darkly Dreaming Dexter" by Jeff Lindsay. The other seven seasons raised from the script written by James Manos Jr. Michael C. Hall received numerous awards and nominations for the role of the main character in "Dexter", for example, the Golden Globe Awards. The other actors playing in the TV series are Jennifer Carpenter as Debra Morgan (Dexter's step-sister, working as a detective in Miami Metro, in real life she is the actor's wife; they have divorced from each other exactly at the same moment when in the "Dexter's" plot Debra realised that she was in love with him), David Zayos as Angel Batista (a sergeant in Miami Metro), Lauren Vélez as Maria LaGuerta (a captain in Miami Metro), C. S. Lee as Vince Masuka (a perverse Chinese police's laboratory worker) and many others...
Source: https://dissectingdexter.wordpress.com/2015/02/01/happy-birthday-michael-c-hall/
The main character of this TV series is Dexter Morgan, acted by Michael C. Hall, working for the Miami Metro Police Department as a blood traces analyst. He seems to be a perfect step-brother, father, husband and employee, but it's only a cover for his actual nature. He has a really dark secret - it turns out that at night, he is a serial killer. However, it appears that, according to his specific codex, he can kill only one sort of people - the killers. Thanks to his extraordinary intelligence, adroitness, analytic skills and a little bit of fortune, he is able to verify if his "target" really is a murderer.
Source: http://erwinreviews.com/the-unworthy-dexter/
I can't tell more in order not to spoil all the plot...
Watch the opening credits of the "Dexter":