I think the TWG is directly responsible for Murphy demise, I don't know why. Perhaps because she was not going to be happy ever again with so many injuries, perhaps because He needs that Harry losses her. I don't know. But Murphy did a wonderful thing, deserving a reward and perhaps Rest is the reward.
Why do I say that he is responsible, because too many "random" things led to Murphy's death. Bradley couldn't move with his daughter and Rudolph at the same time, so Harry and Murhpy asked him to leave Rudolph. The gun dropped to the floor and no one had the time to take it. Then Rudolph completely freak out. And Harry suddenly (not before that) discovered that he couldn't raise his arm for a Forzare. I just think there are too many "coincidences" and I only can see the TWG as having that control over reality.
Dina suggested in another thread that perhaps TWG is responsible for Murphs death. I think it is far more likely to be one of his opposites.
Can you think of anything that is not very elaborate or involves killing children that would be better at making Harry fall than exactly what happened here? It took two whole knights of the cross to counter it.
So I guess there is
Marcone/thorned nashiel
Nic
Lucifer or some demon
Because has the most to win (that I can figure out) and is the only one present in the book I am leaning toward Marcone. If Dresden had killed Rudolf the chances that he could/would team up with Marcone at some point are pretty good I think.
Also, it would be fitting if Marcone was the real killer of Murph.
If it had worked Marcone might end up with an ally and have avoided the eventual conflict with Dresden. Now that it did not, he is just still looking forward to that eventual conflict, even if Dresden finding outwould of course accelerate it.
What do you think?