In the beginning, Atreia was a single world formed around the Tower of Eternity. As the first inhabitants of Atreia the Balaur (the "Draconic" race), became arrogant and powerful. They rebelled against Aion, the Creator of Atreia, and turned into a threat against the world itself. Hence, Aion sent twelve Empyrean Lords to the world to face the Balaur and protect the pillar of the world, the Tower of Eternity. However, the world was devastated after a lengthy war without either side showing dominance.

When the conflict climaxed in the shattering of the Tower of Eternity, the Balaur were forced out of Simabandha and Atreia was split in two. The division of Atreia effectively created two worlds from one. Over thousands of years the separation and semi-isolation, the once united ancestor race evolved separately. One half became the "Angelic" realm, Elysea, and the other half became the the "Demonic" realm, Asmodae. Both are entangled in a bitter struggle to destroy the other side???s remaining piece of the Tower for its own greed and survival. In this endless battle the existence of the Balaur constantly threatens the two races and is yet another factor prolonging the endless struggle of the Elyos, Asmodians and the Balaur.

In addition, the destruction of the Tower of Eternity destabilized the energy flow of the Atreia and created a realm called the Abyss. The Abyss is a mysterious passage between the two halves of the world formed after the great cataclysm. When the Abyss opens up, the Elyos and Asmodian realm's accumulated hatred for each other is amplified and the reemergence of the Balaur foretells yet another great war. Also, secret artifacts hidden from the Elyos and Asmodians that may allow them to gain control the Abyss start to be discovered one by one.

Now, players who are born as humans in the Elyos and Asmodian realms can prove that they are the chosen ones and become a Daeva. They fulfill their mission as both protector and advocate for the higher Gods that they revere and protect ordinary citizens who respect them. In the end their goal is to become the greatest God and to save the world by defeating the other side, who threatens the eternal existence of the world they belong to.