In that interview, which I had previously seen myself, Swen not only confirms DU was a serial killer but also openly refers to DU as a psychopath, exactly as I described the character right from the beginning. He then asks whether, if such a person has amnesia, they are still that same person? The answer to that question is not at all complicated. It is indisputably 'yes.' And for me, it is very troubling that so many people seem to believe that playing a psychopath can be "interesting" and "fun." My two cents.
To each their own, I guess.
Generally speaking, I dislike one dimensional characters whether they be good or evil. When I play an evil character I enjoy the internal and external struggle going on within and outside this character. I usually know that they are both a victim and an executioner... and that is an interesting but dark area to explore as a player. And of course, redemption in one form or another is always an option in my book (though not a certain prospect and not always complete)
Back to the discussion, we do not know the nature of these urges but it could be very well that the Dark Urge character has been infused with that energy without their consent. That vile influence can heavily influence the actions of such a character.