In a new plane...
This is where the dragons live. You have been here once although warned against it. It is a large plane of one mountainous, overgrown world where many creatures roam free. It is ruled by the dragons which were all banished there millennia ago from Celestia when the war broke out.
Not much is know of this plane now as it was left to the Dragons devices. Occasionally a dragon soul falls though to Celestia and is sold by the auction house for a very high price.