Re: I dissagee.
He'll kill nobodies if he has to, but Valeria? That's like Peter Parker killed Aunt May... except with more sexual tension (At least, I hope more than Peter has for May, because that'd just be WRONG).
There should be a tragic romantic (in a psycho way) at the core of Doom's nature, a tortured "might have been a hero if it weren't for that TINY little flaw". Murdering the core of that romantic outlook just doesn't sit right with me.
Doom would also be aware that any deal with a demon has strings, he's battled Mephisto for pities sake...