Vorr
Vorr the Insane is a mad war god and one of the Ancestors who has gone insane with power. He is the main antagonist in The World Tree and The Fiery Moon campaigns. Vorr kidnapped the other Ancestors and imprisoned them on the Fiery moon, so they would not interfere in his plans to destroy the world. Vorr made an alliance between the Necromancers and Barbarians in an attempt to destroy the World Tree. Worshipped by the Barbarian tribes as a war god. When one of the Barbarian leaders (King Targor) defied Vorr after Tarnum showed him the destructive path he was on, Vorr killed him. Although King Targor's barbarian tribe began to follow Tarnum, other tribes still worshiped Vorr. When the World Tree is saved by Tarnum, Vorr returns to the Fiery Moon. There he makes an alliance with the Kreegans and Elementals. When Tarnum defeats him, instead of killing him, he uses the sap of the World tree to heal Vorr's body and cure his mind of the insanity that tainted him. With that, he ceased to be Vorr the Insane and returned to being simply one of the Ancestors.
Of all of the enemies Tarnum has faced, Vorr was probably the most powerful, destructive and difficult one for him to defeat.