“Etheirys was a planet rich in aether, one of the two fundamental forms of energy that make up the universe. Its original inhabitants were known in the future solely as the ancients. They had the power to weave anything they desired into existence, a magick that they named Creation, and which they used to peacefully cultivate their home in the pursuit of perfection. 12,000 years ago the original Etheirys and its inhabitants were split in an event known as the Sundering into fourteen near-perfect copies. The aether of the star was equally divided between them, resulting in beings much thinner in aether who were mortal, incomplete, and without the ability to use creation magicks. Over time, each reflection diverged into its own world, with its own cultures and historical events.”
- Final Fantasy XIV Wiki