Is the main character of GTA IV, Niko Bellic, Serbian? According to Wikipedia, he's Kosovan. If you consider Kosovo as Serbian territory, yes, he's Serbian.

After the war, Bellic couldn't find a steady job so he began working for Russian mob boss, Ray Bulgarin as a worker for his Adriatic Sea human trafficking ring.

"Call of Duty: WWII" is a video game that is set during World War II and strives to depict historical events and settings. While it does make an effort to be historically accurate, it is important to remember that it is ultimately a work of fiction designed for entertainment.

In addition to its focus on intensity and realism, Call of Duty 2 also emphasizes its historical accuracy. All military units in the game actually existed and all of the battles portrayed did occur (although not exactly as portrayed in the game).