Given what I've learned about the nature of the dragonborn, their soul's work vastly differently than usual ones. For one thing, the dragonborn shezzarine is the mingled embodiment of a shard of the Aka-Tusk and Lorkhan/Shezzar. For an individual to have a soul of that size and grandure, it makes it hard to believe that one such as this could actually be vulnerable to the subjugation of the daedra. Am I missing something here, or have I identified this as a potential plot hole?