I have made a post about this in another thread, but as apparently nobody read it I decided to do a new one. As the title says, I've reread Monsters after reading BG-
Viti says that Marcone is bad, is dangerous and he can kill Grey. I think now we know she was not talking about what we thought before, vanilla man doing extraordinary things but Denarian. And I found that very interesting. Also, apparently Grey cannot detect the Fallen in him
Oh, and just a comment. It is relatively easy to make the decision of saving children. As others stated here before, it's not such a great moral thing. I believe the interesting part is that while Grey or Marcone would probably go to some extremes to save children, Harry would probably go to great extremes to save any of them (Marcone and Grey, I mean). And I think in his inner heart Grey wants to be that sort of person, and he is trying. As always, Harry is probably going to influence him to go to that side. Marcone, on the other hand, seems to have decided to go the dark side. But, as I said before, I still see hope of redemption for him. And I still think Marcone himself hopes that, if he ever goes truly, truly dark, Harry will stop him.