One of those reflections─the one nearest to the Source─is our home. And we were the heroes blessed with Her Light. But not all worlds hold Light and Dark in equal measure. In ours, the power of Light was greater by far. So the Ascians who once threatened our home were no match, and they fell before us, one after another, till none were left. Victory, we thought...
...And then came the Light─a flood of pure, blinding radiance, annihilating shadow and color and life itself. Ere long, it will consume our world, leaving naught in its wake but blank perfection.
At the dawn of Hydaelyn's history, the goddess Hydaelyn sealed away the dark god Zodiark, but the process created thirteen reflections of the world. While Ardbert and his fellow warriors fought the invading Ascians, they unknowingly caused an imbalance in the First as the absence of darkness manifested Eden who consumed the First in a light. Some of the afflicted denizens transformed into monsters called Sin Eaters, which plague the remaining people for a century. By the time of Shadowbringers, Norvrandt is the only region not succumbed to the Flood of Light that has turned the rest of the world into a wasteland known as the Empty.
While the First at its base is a perfect reflection of the Source from the time the worlds split, millennia have passed resulting in drastic differences in the worlds' histories. Nearly everything familiar between the two goes by a different name, cities appear where there were none in the other world and vice versa. The familiar races of Hydaelyn may all appear in the First, but their cultures have diverged drastically to the point of being alien.