A rebel leader, Rex propped up the individuals who felt the leadership of Tersce Tenebrosi and company was lacking. The former Commander elected to stage many conflicts on other worlds, chiefly in pursuit of crystals that would be able to make the Thep Khufans more powerful. In focusing all his efforts on these outer expeditions, there was no attention given to the people living on-world. The Commander was acting as just a General when the role needs to belong to someone who acts as both Commander-in-Chief and leader of the world of Anur Khufos.
In Back in Action: Alien Universe, Rex debuted in Ben 10: Alien Universe Unleashed where he and key rebels like Plasma shared their story with and aided Ben and the 10 Squad with defeating the Armada and implementing the new government under Rex.
He returned in Fate of the Helpers, comfortably leading the world with Plasma as his aide.