User blog comment:Woest/The Light and Darkness of the Guild/@comment-24467372-20140316110821

This is a good theory but I don't think that'll be the case.

It's either 1-)A pocket dimension where the Dragons are hiding. That's what Gildarts saw. A giant canyon with Dragons flying in the air. 2-)A time portal to 400 years ago. And this is the way that Natsu traveled into the future. And this is the reason why he couldn't get out of Freed's runes. Because he is 400 years old.