Velen, the holy leader of the Eredar Remnants from Argus called the Draenei, meaning something like "Redeemed ones" in the Eredar-language... He was one of three Leaders of the Eredar Planet Argus and had a very close connection to the holy light and the Naaru, and that is why he refused Sargeras offer of gaining incredible powers in exchange for loyalty, which Archimonde and Kil'Jaeden (Argus's two other Leaders) greedly took. He, unlike the other two could see into the future and knew what Sargeras tried to do, therefore he fled with some loyal Eredar to another planet in Naaru-ships... The other planet was Draenor, home of the Orcs in the first and second war (And before) and in many years the Draeneis and the Orcs lived in peace together, but then Sargeras came and corrupted the Orcs too, and Velen's forces was forced to flee yet again... This time they only had one ship left (What the...! Why?): The Exodar, and that one crashed into some small island on the planet Azeroth and eventually joined the Night Elves and the Alliance against Sargeras and the Buning Legion...