First off, I'd like to dispute the "extension of the DO" theories... Sure, they're interesting, but what about Shaidar Haran's thoughts when he was following Graendal and Sammael after their meeting w/ the Shaido? I don't have the exact quote, but it goes something like, "He could feel himself getting weaker. Too long from SG and the DO sapped his strength. There must be some way of getting rid of that attachment." The fact that we can even see a bit of his thoughts points away from this theory. Also, because he wants to get away from his attachment to the DO one can infer that he has an independent mind... Therefore, not literally the hand of the DO. Personally, I think he's just a whacked-out Mydrraal.