Niko Bellic was born to Milica Bellic and her husband in a small village located in modern-day Serbia, and had at least one brother. His family lived near to his paternal uncle's family. Niko grew up closely to his uncle's child, Roman, and the two would often play with each other, becoming best friends in their adult years.
Both Niko and Roman suffered from their fathers' sadisitic, violent behavior, who also used to beat their wives. According to Roman, their fathers stopped beating them once they were too drunked to do so. As a child, Niko once had a dream of becoming an astronaut.
The village Niko grew up in was very poor, and did not have electricity until Niko was twelve, circa 1990.
- "When I was in the army... we were going on a mission... to ambush a squad who had killed a lot of innocent people. They were our enemies... But we never did it. There were fifthteen of us, all boys from the village. But one of us betrayed the group. It was a setup... for money! Twelve people died, three escaped. I know the traitor was not me. So for ten years I've been searching for the other two."
- ―Niko reteeling the events of the war to Roman.
When the Yugoslavian wars started in the early 1990's, Niko and his older brother were two of the many child soldiers that joined the army, much to their mother's dismay of her sons being raised in such a harsh environment. Roman, on the other, decided to move to the United States of America in order to escape the war, receiving help from his mother, who sent him money to start a new life.
Niko, now a teenage soldier, was joined into a fifteen man squad consisting fourteen other children from his village, including Florian Cravic, Darko Brevic, Goran (the squad's leader), Dragan, Mijo, Dmitar and eight additional soldiers. According to Niko, eight people from the deceased squad members were his personal friends.
During one of the squad's missions, they were sent to ambush and kill an enemy squad that murdered several civilians. Unfortunely, they were discovered and all but Niko and two other members of the squad were killed. Knowing that it was impossible for his enemies to know about the ambush, Niko understood that they were betrayed in-side the squad. The same night after the ambush, Niko went back to the place; he started digging through the bodies, noticing two missing members: Florian and Darko. It was then where Niko vowed revenge on the traitor, although he didn't know which of them was the one.
On one occasion in the war, Niko bore withness the mass murder of fifty children in a small village by enemy soldiers. On another, Niko found his aunt - Roman's mother - murdered. Horrified, Niko lied to Roman and told him she died in a house fire, keeping the truth for himself for the next decade.
Ultimately, all events in the world scarred Niko for ever, earning him his infamous sceptical and dry on world-view.
Working for Bulgarin
After the war was finished in the mid 1990's, Niko, like most veterans, had difficulty finding a stable job. Having no other choice, Niko decided to turn on illegal human trafficking for the Russian buisnessman and crime-lord, Ray Bulgarin. Niko was successful in his job, but unfortunely, during one smuggling run into Italy, the ship was busted and Niko had to swim for his life. Despite Niko couldn't do nothing to save the ship, Bulgarin nevertheless blamed him the loss, attempting to hunt him down.
Niko, having no other choice, escaped Earope on a boat, the Platypus, after joing merchant navy