Vosk in the year 1944 of an alternate timeline
Vosk was the leader of the Na'kuhl, a faction in the Temporal Cold War. Originating from the 29th century, Vosk was strongly opposed to the Temporal Accord, believing it was his right to use time travel for the benefit of his race.
Vosk was perceived as being the most dangerous participant in the Temporal Cold War by Daniels' faction, and he was once very nearly captured by them. However, Vosk developed a form of stealth time travel, and he and his followers escaped to the 1940s on an alternate Earth. Vosk wanted to return to the future and defeat Daniels and his cohorts, but since his time portal had been one-way, he was forced to ally with Nazi Germany, who in this history had been able to conquer the eastern portion of the United States of America as an indirect result of the assassination of Vladimir Lenin in 1916. Vosk's people bribed the Nazis with offers of advanced technologies (such as enhanced Stukas) in exchange for the resources to build a temporal conduit. However, Vosk refused to trust the Nazis with technology that could be used against them and instead merely offered promises and excuses in order to buy time for constructing the conduit.
Vosk was often at odds with the German Generalmajor serving as the liaison between the Nazi party and Vosk's people, who grew impatient at Vosk's stalling. When Vosk and his people were preparing to return to their own time, the treacherous Na'kuhl leader ended his alliance with the Nazis by killing the generalmajor.
Vosk's plans were ultimately foiled when Daniels and Enterprise arrived in the year 1944, intent on stopping Vosk from returning to the future and igniting a full-blown Temporal War. When Tucker and Mayweather were captured and brought to Vosk, the Na'kuhl surmised that the crew of Enterprise were not temporal agents as he had earlier feared, but did suspect their presence in the past was no accident or coincidence. A conversation with the ship's captain, Jonathan Archer, later confirmed his suspicions.
After releasing Archer's crewmen, Vosk attempted to secure a pact with the starship captain, promising to send Enterprise back to its own time if Archer gave Vosk access to the technology aboard Enterprise which he believed would greatly accelerate the construction of the conduit. After Archer refused and with the Germans having ordered Vosk to relinquish command of his squadron to Hitler's men, Vosk decided he and his people would enter the conduit despite previous failed attempts to keep it open. Although his associate, Kraul, was concerned that the conduit would not hold, Vosk believed it was their destiny for them to succeed.
Vosk and his men were killed when Enterprise destroyed his compound, just as Vosk stepped into the temporal conduit. (ENT: "Storm Front", "Storm Front, Part II")