4. Issak Surko (Season Seven)
Though he may not have finished off as a villian this one man wrecking machine was one of the coldest and brutal that Dexter ever had to encounter. Issak was one of the main antagonists in the early part of Season Seven. The head of the Koshka brotherhood Issak was on a one man revenge mission against Dexter after he killed one of his men, Victor, who it turned out was actually his lover. Issak showed no mercy as he hunted down Dexter, killing another one of Dexters problems Lewis, forcing a man to commit suicide in order to take police attention away from his men and killing a whole pub full of men singlehandedly. Dexter and Issak ultimately ended up joining forces to defeat a common foe and Issak was tragically murdered by a man who used to work for him. His final scene with Dexter on the boat was one of the best in Season Seven. The more Issaks character unravelled the more intriguing a character he become, he and Dexter shared some of last seasons most memorable moments and his death was a little too premature for my liking.
Defining Moment: Forcing a man to write his family a suicide confessing to a crime he hadnt committed in order to save one of Issaks men.