Here's some info that I gathered to back up my Theory:
- Dampé worked in the graveyard, where many poes gathered at night
- The graveyard boy was a BIG fan of Dampé, so if he were to die, he would do anything to bring him back
- The Poe collector said that he used to live somewhere in Hyrule
- The Poe Collector also said that he was collecting Poes for a reason
The Poes might have killed him but since they seem to leave him alone when they appeared at night, it doesn't really seem likely that they'd just suddenly decide to murder him.
I'm a BIG fan of Michael Jackson but I've never thought to try to resurrect him. The boy would no doubt have been sad at Dampé's death but it's a bit of a stretch to say he would do anything to bring him back.
The Poe Collector describes what he does as a "business" so his reason for collecting Poes seems to be, at least to some degree, a financial thing.
"Because of the great Ganondorf, it is a fine time for a business like this... heh heh heh... Oh...I can only hope the world gets even worse!"
Everyone its not about the poe colecter its about the dampe thing I think its a good thery The kid coud be whereing the Mask Of Truth so he looks like he has one eye.
Well the theory is in two parts, firstly, that the Poes killed Dampé and secondly, that the little boy became the Poe Collector and brought him back as a ghost, so the identity of the Poe Collector is equally as important here.
Personally, I find it unlikely (but not impossible) for the Poe's to have killed Dampé. Although they leave him alone when they appear, after Ganondorf took over, perhaps they became more aggressive.
As for the young boy being the Poe Collector, I find that extremely unlikely. Yes, there are things to suggest it but the evidence pointing at the Guard who was posted to the same room in the past era is much, much stronger.
The little boy and the Poe Collector share a stick and not much else. The little boy gets annoyed at Link when he moves the gravestones, ("Don't cause trouble! I'll tell Dampé!") showing he doesn't like trouble and he complains about having too cute a face. The Poe Collector revels in chaos and disorder and hints that he has an unpleasant face:
"If I looked as good as you, I could run a different kind of business...heh he heh..."
Furthermore, the Poe Collector refers to Link as "young man", suggesting he is older while the little boy was clearly younger than even Young Link.
As for the Guard, well, almost everything he says backs up the idea that he is the Poe Collector:
"Man, I am SO bored... Things would sure be more interesting if there were more... troubles in the world..."
"Man, I am SO tired! The night watch is so boring! I wish some ghosts would come out or something...."
"Hey, I'm really interested in ghosts! Studying them is a hobby of mine, but you never know... the time might come when that kind of knowledge might be useful!"
That last quote in particular seems to all but confirm the Guard as the Poe Collector, especially since he says that and when you enter the exact same spot 7 years later, there's a mysterious man in robes resembling those of the Hylian Royal family (who the Guard would obviously have had some contact with) who collects ghosts and desires for the world to become even more troublesome.
To sum up, the little boy likes Dampé, not ghosts (since he's never there when the ghosts show up) and certainly not trouble, just Dampé. The Guard loves ghosts and loves trouble and desires both in large quantities, exactly the same as the Poe Collector.
The Poes may have killed Dampé but I would doubt it and it seems highly unlikely that the little boy became the Poe Collector or would have really tried to bring Dampé back from the dead.