Yeah, "you on your worst day" is sometimes simplified to "your opposite" in this here forum, but that's not how it works. Vamp Durkon doesn't seem to be merely Hel's puppet, he has his own goals and desires, but so far there's little reason to suggest that makes him any less loyal to Hel. I do think he could (and perhaps will) become sidetracked and lose sight of his end goal, but that'd be because he'd get carried away, not because he'd consciously choose to defy Hel's orders.