Er... [Right, this is a guy that's all about Science.] Aether's something that exists in all living things and throughout the planet. Without aether, you have have no life or magic. Which is why if you use up too much of your own aether, you'll die.

But if you're around too much excess aether, it can be just as bad, and can kill you or drive you mad. It takes time to replenish from the world around you, and how much aether someone can hold within them varies from person to person. Enough excess aether in an area can affect its weather.

Aether sometimes forms crystals if there's enough of a concentration of it. They can be used as an energy source and can be aspected to different elements. We've learned how to fashion large crystals called Aetherytes that you can use to travel to any place you've been to before with an Aetheryte using the aetheric streams that course through the planet.

... That's more or less all I know. I'm the giant axe swinging man, not a healer or mage.