Swimmer Civil War

Atharia used to have a lot of magic.

3000 years before the settlers arrived on Atharia, the Swimmers fought a long and bloody civil war. Wanting to put a swift end to it, one faction unleashed a devastating magical attack on what is now known as the Datroya Plain. The spell warped the land and every living thing inside it. The people living there mutated, becoming what are now called khollu.

Initially confined to the Datroya Plains, the khollu spread out. Few studies have been made on them. It's unknown how they reproduce or even if they do so at all. Some scientists theorize that the khollu are effectively immortal, though they can be killed. They can and will eat anything they come across. The arrival of the settlers did much to repair the damage the khollu had done to the ecosystem.

Though it was unknown at the time, this spell had a secondary effect. It destroyed much of Atharia's aether and polluted what was left. In time, the aether would replenish, but it was never the same after that. The surviving Swimmers put a ban on magic that lasted until the settlers arrived. Arriving Gifted couldn't adjust to the tainted magic. They sickened and died.

Gifted who didn't use their abilities fared better, though they had difficulty having children.

Some of the Gifted made it their life's work to cleanse the aetheric currents, but ultimately failed, the project ending with their deaths.

When religion was banned on Atharia, it made sense at the time to eradicate as much knowledge about magic as they could. At the time, they saw it as a safety precaution. If people couldn't use magic, it wouldn't take their lives.