In the world of Ashura there is a constant battle between the dark and the light and, each one has its avatar. In each generation, a new avatar is chosen to be the beacon of each faction when the old one dies. The new avatar has no choice in the matter and when they are chosen they embody all the aspects of their faction. This was true for Damien, as he did not choose to be the avatar of the dark, it was forced upon him.