Vassily Barkov was a minor character and antagonist in Volume 5.
He was first introduced in the bonus scene of chapter 4, when Genevieve issued Shawn Mallory -- a then vigilante -- a new target -- a human smuggler named Barkov.
Barkov appeared first in V5C7, where he -- using a bar as a front -- was a human sex trafficer. He took a Russian woman, Nika Eltsina, hostage; Shawn and her had a one-night stand, and Shawn promised to buy her freedom. When Shawn attempted to give Barkov $20k in cash and Barkov took the money as a down payment against Shawn's will, Shawn killed Barkov's bodyguard. When Mal and Natara barged in, a triangular stand-off occured between the 3 parties. Mal and Natara one one part, Vassily holding the prostitute on another, and Shawn at the third.
Ken barged into the situation (V5C8) and opened fire; as he did, Shawn fired at Vassily. Alibeit critically injuring the prostitute in the process, Shawn did kill Vassily.