"He was possessed, not an abomination. Not in full. He might have been had the Hero of Fereldan not completed that ritual. The semantics of this are...complicated mostly due to there being many theories, few opportunities for actual research, and a distinct inability of mages to make up their minds with or without the Chantr's input. The demon in Redcliffe likely channeled it's power through Connor much as I would channel Compassion's power in healing."