I'm pretty sure that Corpsetaker died when Harry killed him, and he just stuck around due to the whole "death is a spectrum" thing.
Thank you Nadia, I am glad the point I am trying to make isn't getting completely lost.
Mira - If it helps, from the perspective of a Mortal with no supernatural awareness (in the Dresdenverse) death seems very final. You are gone when your brain gives up. And we can only speculate and use the knowledge we have to guess at What Comes Next. But as readers, we know differently. Like anyone with awareness of the supernatural in the DV, we
know that there are many different afterlife realms (Heaven, the Greek Underworld, Hell, Gehenna etc).
So when the Corpsetaker died (in Luccio's body) the body experienced the scientific process of death. Corpsetaker's spirit left that body and went Between rather than straight to What Comes Next. The difference between being
dead and
gone. We don't know why or how. And yes, the final dissolution of the Corpsetaker into What Comes Next did come at Mort's hand in Ghost Story. But Death is a
process, not an ending. That is clear in our universe, and in Dresden's. You can see in the DV that a person's Spirit/Soul leaves the Mortal/Material plane and goes into the Spirit part of the Nevernever (I define Between as slightly different than the regular Nevernever as it must be much further from Dresden's world than say a place like Faerie, where the rules are mostly the same). Beyond even that, there is the after-after life (Heaven and Hell etc). Which again, does not mean the Corpsetaker stops existing. Far from it, the Corpsetaker now has to deal with being in wherever it went (presumably Hell). Which is not to say it couldn't come back either. Rare, but not impossible. Food for thought.
Cozarkian - I will create another thread to expound on the whole Summer/Bad Guys connections. Yes I had considered that the Corpsetaker must have had some knowledge to stop him/herself passing on fully. I think you are essentially right, the act of using the Death Curse at all might have precluded the Corpsetaker from being able to survive as a spirit in Between. Kemmler may have thrown a Death Curse - believe that there is a theory floating around that his Death Curse was the Tsar Bomba explosion. However, it may also not have been as I believe JB said that the White Council put a magic lock on him (like Eb did to Mavra) so that he couldn't use magic, and they cut him up and burned him. This was how he wasn't able to cheat death again presumably, though of course we don't know that he isn't active from beyond the grave...