He created the world itself, as well as the Humans and the Balaur that occupied it. The Balaur were to rule the planet's population and be the protectors of Atreia and of their Human counterparts within the world. Inside the world of Atreia, though no star could reach, the light of Aion kept the world bright.
Rebelling against their position of servitude and their growing obsession of power, the Balaur eventually turned and began using their power to try and take over the world of Atreia. This led to Aion's creation of the Empyrean Lords. Aion also saw fit to grant certain Humans god-like powers. These beings became known as Daevas. The Empyrean Lords and the Daeva were appointed to protect the Tower of Eternity, Aion's physical presence on Atreia. It is only through Aion's will that a human may ascend to become a Daeva.