Vorador may have been born towards the end of the Vampire/Hylden war, or shortly after. The order of the murals in Defiance suggest that the Pillars were raised (and the war ended) before Vorador forged the Reaver, and that he forged the Reaver before he received the 'Dark Gift'.
There's nothing to suggest that Vorador was coerced into either of these acts - both of which were for the good of the Ancient Vampires. For whatever reason, he wanted to help them, and continued to care for the well-being of his sire, Janos, for many centuries afterwards. It is only stated that the human successors to the fallen Vampire Guardians were abducted, and that prompted hatred and eventual revolt from Moebius and Mortanius. It's unlikely Vorador's loyalty to the Vampires came about because they kidnapped him.