As their elements (fire and ice) suggest, they do not get along very well. Their first scene together shows that they are, at best, tolerant of one another. As Vexen is about to go test Sora, Axel throws him a card. It may seem like a trifling act, but Axel's intentions were to get on Vexen's good side to avoid any interference with his own plans. Vexen had no idea that Axel would soon be ordered to eliminate him for almost telling Sora about Roxas. Axel thrusts his chakrams into Vexen from behind, ignoring the cry for mercy that he desperately lets out before dying.