In the video game series, Sergei is a former Soviet Union Colonel, who lost his home at the end of the cold war. When this happened, Spencer (founder of Umbrella Corporation) gave (him) a home... and a purpose. Fiercely loyal to Spencer and Umbrella, he quickly suspected Albert Wesker's treachery and the two were engaged in a five-year rivalry which ended in his death in Umbrella corps' Russian facility. During this battle, he revealed to Wesker that he is the source DNA of what became the Tyrants. Wesker killed him and stole the data, which he anonymously submitted to the Federal Bureau of Investigations to bring down Sergei's benefactor - Spencer.In the film series, Sergei is a much more benign presence, as he helps Leon S. Kennedy and Barry Burton in their mission to retrieve Alice, but dies in a fight with the undead. Once again, dying in an Umbrella facility stationed in Russia.