We are told that Kemmler used this exact technique of devouring spirits (not souls) as fuel for his own power, and the more powerful the spirits, the more power he gets from it; all in service to exposition of his evil insanity.
We Also know that memories are important to ghosts. No more memories, no more ghost. When sir Stuart shot the ghost, he used memories as a bullet. And he got "energy" back from the remains of the ghost. If I recall correctly, Harry did something similar while being a ghost. The fact that you can do something similar does not make you Kemmler.
Besides, We have been speculating that Kemmler could jump bodies like Corpstaker. It seems far more likely that he jumped bodies before he died than that he somehow was reborn in another body without the memories, drive and desires. Simon for example was fighting him and could be one of the people he jumped into (his disappearance/death later being a great way for him to return to his old dealings). Then again this does not explain how Kemmler returned the first time. It would help a lot if we had more info on Kemmler (besides how he did it
). Things as, Did the returned Kemmler have the same body? Was he helped with his return? Were certain items important in the returning process? etc...
So I do not believe that Harry is Kemmler reborn. Evil Bob would have recognised Harry as being him. But you and others make a valid point that the darkness in Harry must be explained somehow.
D-E-D dead is Jim emphasizing dead and being cute at the same time.
I might be mistaken, but isn't "
Dead, D-E-D Dead" also a movie quote?