I hope we'll get to learn the truth of what happened in the Burn to make it the way it was now that we're journeying to it presumably to rescue Alphnaud from the imperials and/or whatever nasty beasts dwell there.

If it was really a multitude of primals that stripped the land of its aether, someone had to have summoned them and judging from the decrepit building present in the sole screenshot we have of the place as a dungeon, it seems like it probably was home to a civilization before it was destroyed.