One last thing: why does Zeref say that Acnologia ended history once? When was it? 400 years ago?
And how do you even end history?
I could understand that he change the flow of history, but ending it…
Could it be that Natsu and co were actually hibernating for a few hundred years when the dragons chose to go inside them and only woke up a few years ago not finding their dragon parent's around?
The only problem with that is we don't know when the dragons actually disappeared. They said it was 7/7/XX77 or something, but how did they know which year it actually was indeed? The only dragon met by other mages was Acnologia, we never hear about other mages meeting other dragons. But people should have told Natsu and co if the dragons had actually disappeared earlier.
Also, Natsu had to be grown up to be END, so he certainly was reincarnated as a kid, in any case. But since Wendy, Sting and Rogue are younger than Rogue and Sting, it could explain why they were not all "born" again at the same time… It's so confusing.