Oleg Stark was the main antagonist of the Grimm episode "Game Ogre."
Stark was a contact killer wanted for murders in Illinois, North Carolina, Kansas, Washington, and Colorado. Around March 2007, his business associate Jack Lambert stole Stark's secret gold stash after discovering that Stark demanded to be paid in gold. In revenge, Stark abducted Lambert and his family, torturing them for two days before murdering them. He was arrested by Hank Griffin, and held on trial in Portland on March 11, 2007. During trial, Stark had a lawyer submit evidence to prove Stark was innocent: Stark was supposedly captured on camera at a restaurant at the time of the murder. Looking at the footage, Hank noticed that the man was not Stark, but a look-alike placed there by Stark to convince the jury that he was innocent. Knowing the truth and what it could mean if the evidence was shown, Hank "lost" the evidence". Stark was sentenced to 300 years in prison at an ADX facility in Pelican Bay State Prison, Crescent City, California.
5 years after the trial, in 2012, Stark broke out of prison while on medical transfer; he beat two guards into a coma and broke the doctors legs. On returning to Portland, Stark went on a rampage looking for revenge, as the Siegbarste race is renowned for taking grudges to the grave.
He first attacked the district attorney who prosecuted him, cutting out her tongue and placing it on the scale, and stealing her watch. Then he attacked the jury foreman who gave the verdict, murdering him by cutting his hand off, and then placing the district attorney's watch on his other wrist. Finally, he killed the judge who sentenced him, murdering him in an unspeakably brutal method of forcing his gavel down his throat.
After this, Stark began searching for Hank to end his vendetta. He blew up his car near Hank's old residence, unaware Hank had moved. Still getting nowhere, he broke into Nick's home. Nick tried to fight back, but Stark's superior strength and durability proved too much. He tried to beat Hank's location out of Nick, before realizing Nick was a Grimm and thus could see his monstrous appearance. This caused Stark to turn more violent. At that moment, Nick's girlfriend, Juliette, returned. Panicking, she tossed a pot full of boiling water over Stark, distracting him long enough for Nick to reach his gun. After firing at Stark three times, Stark retreated but had to Nick to be hospitalized for his injuries.
Meeting up with Monroe, Nick remembered that one of his ancestors' diaries had described a weapon built to combat a Siegbarste A three barrel elephant gun, with bullets coated in a special poison could kill even Stark. With Nick incapacitated Monroe would have to get the gun and stop Stark.
Meanwhile, having finally driven him out, Stark met Hank. Hank tried to fight, but Stark easily threw him to the ground, and he lifted a giant stone slab, intending to crush Hank. However, Monroe had collected the rifle and shot Stark in the back while hiding in the shadows. The gun and poison proved too much even for the giant ogre, and he was killed.