Driscoll Connor (commonly referred to as F8 or the Infinity Killer) (Brian Chamberlain) is the main antagonist of the Dexter Alternate Reality Game. This killer started a cycle after a situation dealing with the Roulette Killer back in his younger years, leaving a sideways "eight" at every crime scene...also known as the symbol for "Infinity".
Infinity is an attractive white-male in his 30's with short, somewhat spikey black hair and a square-featured jawline, overall making his face appealing. He typically wears a large pair of black sunglasses but can be seen without them, revealing his eye color to be blue.
He appears to be a rather fit individual, which would support his ability to kill a number of his victims and his height seems to be between 5'9" and 6'3", with tanned skin. His typical attire appears to be white button up shirts and khaki pants or bluejeans (much like Dexter himself).
Infinity has a rather complex personality, as a character he cares about those that supported his actions while he still killed for his own purposes.
Appearances in Other Media
While Infinity himself hasn't appeared in the Showtime series, a symbol often used by the killer is found on a door during Episode 501: My Bad, located in the lower right corner as Dexter enters the bathroom where he kills Rankin. It's drawn in blue, that of an Infinity mark.