Aion is all about the bitter clash between ‘the Angelic realm‘ and ‘ the Demonic realm’, the infinite battle with the Draconic race is all through Aion, and this is threatening all of these.
At the very beginning, ‘Atreia’ itself was a single world formed around ‘ the tower of Eternity’, at the same time the ‘Draconic’ race becomes arrogant as its power gets more strengthened. The ‘Draconic’ people get unfriendly to its creator and is with the purpose of conquering Atreia. The creator is afraid that the Draconic will have no rules to follow and is not under control, so he sent twelve Gods to the world to face the Draconic race and protect the root of the world. The result is not ideal.