The draenei (exiled ones) were the faction of uncorrupted eredar from the planet Argus led by the prophet Velen. When Sargeras made a pact with Archimonde and Kil'jaeden, Velen fled with loyal eredar with the aid of the naaru Ku're, and began moving from planet to planet to escape the Burning Legion's wrath. About 200 years before the First War, they settled on Draenor, until blood elves of the planet Azeroth took over Tempest Keep, during which the draenei wrestled control of the Exodar and escaped Draenor. However, their engine went haywire, making them crash land on the planet Azeroth, where they now reside.
During the Burning Legion's third invasion of Azeroth, Legion forces led by Rakeesh invade the Exodar to slay O'ros, the naaru in the Exodar's core. While he was successful, he was slain afterwards, this being a vision seen by Velen. Rakeesh turned out to be his son, who he had believed dead at the hands of Kil'jaeden. Velen then ordered Romuul to begin repairs on the Exodar, stating that the draenei were going home.