Gordei Volkov was a Russian hitman in league with the Covenant.
Gordei was first spotted with a group of hitmen who shot and killed several civilians on a passenger train looking for a man named Scott Kingsley. When they found him, Gordei shot Scott in the leg and demanded to know the location of a chip. He told him it was in his shoe (after Gordei had to stab him once) but as his men analyzed it, it wasn't what they wanted. Gordei found the real chip in his pocket after stabbing and killing Kingsley again, which contained schematics for a spy drone.
Sydney, Weiss and a team of CIA field operatives went into a Paris hanger to retrieve the chip, but it was trap set up by Gordei and his mercenaries. All of the CIA field operatives are killed (except for Weiss, thanks to Sydney) and Gordei and his team escape with the chip again.
Sydney finds Gordei in Prague driving in his car with three of his henchmen. She takes out a gun and fires and RPG at the car, blowing it up and killing everyone inside. Gordei escapes at the last second and the two have a short fight. Gordei pulls out a knife and Sydney kicks him into a wall. When Gordei turns back around, the knife is lodged in his torso. Sydney retrives the chip and drives away, leaving Gordei to bleed to death.