According to the game's backstory available on gpotato's site, the oldest race is the Gaia, and to assist them, the gods of Creation and Extinction brought two more races into the world. They were the Deva who represented the Light and the Asura who represented the Darkness. With this, there was a period of peace and stability in the world.
As the ages passed by, there was one among the Gaia who called herself "The Witch". Over time, she grew in tremendous power and with a ruthless ambition, rallied the people of Gaia to rebel against the world.
Not all the people of Gaia heeded this call however and the world was thrown into chaos. It was only through the combined efforts of the three races of Deva, Asura and Gaia that "The Witch" was finally captured and burnt alive. It was a victorious outcome of a unity between the three races.
Now at the present time, the three races continue to co-exist with each other in the world of Rappelz but dark rumors have surfaced about the second coming of "The Witch" and the return of her terrible forces.