Khossa Vole was a necromancer who once inhabited the land of Surdana. The people rose up against him to prevent him from bringing an undead scourge upon them. General Dehrimon fought the necromancer in his youth, apparently killing him.
Many years later, it was discovered that the necromancer was not dead. He had separated his spirit from his physical form and hidden his body away, permitting him to continue existing. What's more, he had found the Gravestone, a necromantic artifact from the days of the Dark Union. The stone gave Vole immense powers to create an army of the undead.
Drakan: Order of the Flame - Drakan: The Ancients' Gates