Darko Braznev

"Niko Bellic: Reci mi zašto. Darko: Žašto? Niko: Zato jer smo bili prijatelji. Svi smo odrasli zajedno. Dmitar, Dragan, Goran, Mijo... Mogu da nastavim svijo?! Ah? Darko: We were friends, but I had other friends! Friends that Goran and his guys killed. My fahking neighbours!"

- Bellic and Darko's convo when Braznev gets taken to him

Darko Braznev is a central character and the tertiary villain and former mentioned villain of Grand Theft Auto IV. He was one of three survivors of the Fifteen Man Squad, the others being Niko Bellic and Florian Cravic.

Biography
Darko was a fellow soldier who served the Yugoslavian Army alongside Niko Bellic and Florian Cravic during the Yugoslav wars. However, he eventually sold out his squad to enemy forces in Albania for $1,000 to help pay for his heroin addiction.

Niko would spend the next decade hunting down Florian and Darko to discover who betrayed the squad, and to exact revenge.

Niko moves to New York to find Florian, who in the intervening and out-of-the-closet years; changed his name to Bernie Crane. Niko discovers, however, that Florian is innocent, and begins to search for Darko.

One of Niko's contacts at the United Liberty Paper organization, Edward B. Fortune, located Darko in Bucharest, Roumania. Darko was kidnapped and brought to New York City, where he is left in the cargo bay of Francis International Airport, at Niko's mercy; Niko arrives at the airport with Roman, and interrogates Darko.

Darko reminds Niko that their squad were "no angels" themselves, stating that Goran Milovich was responsible for the deaths of some of Darko's own friends and neighbours, and tells Niko the reasons he betrayed the group: 1 mere buck. Niko is horrified that he and his friends were sold out over such a paltry sum of money; in response, Darko asks how much Niko has charged for all the murders he has committed. Darko also calls him a hypocrite which he technically is. He then falls to his knees and says that Niko would be doing him a favour by killing him. He breaks down in tears, and Roman attempts to coax Niko away, observing that Darko "doesn't look like he enjoys life too much."

Death
Despite Darko's pleas or maybe because of them, Niko Bellic pulls out a glock 9 and shoots him twelve times, one shot for each of his lost friends. Darko thanks Niko as he dies, and Niko walks away feeling, as he later says to Roman: "empty." It seems like the revenge was not satisfying one bit. He later calls Florian Kravic and tells him that he killed Darko by which Florian is horrified by.

Personality and traits
Darko betrayed his comrades/bros in arms, motivated by money, and the fact that members of his squad had killed his neighbours and own friends. After the betrayal, his life on the run has taken it's toll on him in Roumania, transforming him into a miserable drug addict. He is very pessimistic about life and everything in general as he reminds Niko that killing him would be doing him a great favour.

Trivia

 * Darko looks quite similar to Niko Bellic himself, or at least looks like his older brother of sorts.
 * In the current timeline, he, like the Borlinghathen brothers and their godfather was killed in 2018.