Deretić was an engineer by training but was mainly noted for his pseudohistorical and conspiracy theories.

According to Deretić, prior to the conquests of Alexander the Great, there lived an even more-accomplished conqueror named Serbon Makeridov, who was "father of all nations" and that "all of his descendants, or rather all known peoples, have Serbian origin".

Deretić asserted that existing historical research is evidence for these theories but his interpretations have been universally rejected and heavily criticized by professional historians.

[3][4] Deretić organized a petition drive of Kosovo Serbs requesting Russian citizenship: "Ethnic Serbs in Kosovo would feel more protected, if Russia granted them citizenship.

"[5] Deretić said he gathered 72,500 signatures from Kosovo Serbs who wanted to adopt Russia as "a second Serbia" that would protect them against anti-Serb violence.