Dimitriov was the self-styled president of the Russian Republic and its military founder. Originally a general in the Russian Imperials Army, Dimitriov consolidated his power in central Russia, seizing power in the foothills of the Urals through political murder and consolidating the forces of the enemies he killed, or from those who joined him. His moves ultimately lead to the rise of the Russian Republic in 1975. Ultimately, Dimitriov was forced from power when the Chinese demanded his arrest at the Conference of Moscow following the Russian-Chinese VX Crisis. Dimitriov was removed by his own government and handed to China, fearing continued Chinese aggression on their eastern borders.
It would be in a Chinese prison that he dies.
Dimitriov's background is lacking in details, but it can be surmised he had a career in the Russian military before the Empire's collapse in 1971. He was a high-ranking officer who negotiated the minefield of Russian politics after the czar's death to build his own self-styled Republic.
His term in power is considered to be chaotic, if powerful. His Republic managed to stop the course of the Chinese campaign through Russia and turned them back. And in some way may have been connected with the Russian Resurrection. However his failures to maneuver the Republic through the Resurrection was ultimately tied as he had been removed from office by that point.
Following the indicating threats to procure and use the VX nerve-agent on China, Dimitriov's arrest was demanded by China as a point to cease military campaigns in Russia. The Republic obliged the request and handed the president to the Chinese. Though he was not determined to be executed by the Chinese he died in prison anyways.
The official story was that a riot had broken out in prison, which resulted in the unfortunate murder of the president by an armed inmate who was himself killed. However, the real situation entailed a prisoner taking offense at the president's place in the food line and his taking of an apple that resulted in the president's murder by the prisoner. The offending prisoner was later transferred.