The player controls Niko Bellic, an immigrant from Eastern Europe.
According to Dan Houser, "virtually none of the characters from the previous games returned, as the GTA IV era is set in a parallel universe compared to the GTA III era.
He is shown to arrive on the boat from the Adriatic Sea, along with a pack of prominent diamonds smuggled into the United States, which serves as the game's plot. According to Niko, Roman's mother was raped and murdered during the war, although Roman believes she died in a house fire; to this day, Niko could not find it in his heart to tell Roman of his mother's true fate.
Roman claims to be living the American Dream to his relatives and that he has two women, four hot tubs and fifteen sports cars.
In the "Deal" storyline, Roman is inadvertently killed at his wedding by an assassin sent by Dimitri, in an attempt on Niko's life.