During the Amani invasion of Quel'thalas, many elves were slaughtered. An ultimatum was given by Warlord Jin'thek, to bow before trollish rule or perish. Proud by nature, no elves dreamed of surrendering themselves to the wrath of the Amani. Few prisoners were taken regardless.
Once Silvermoon City had fallen, however, those elves who had suffered under Anasterian or who had come to loathe the opulence of elven civilization began to creep out from the cracks of the world. Then there were those few who had witnessed genocide of the trolls, and pitied them, understanding their vengeance. The great inequality in lifespan between the elf lords and their servants was also a marked cause for complaint, as the nobility outlived their followers by millennia due to their greater access to ancient magics.
These rebel elves were joined by those who sought to negotiate a place for the elves in a trollish dominated world, and formed the Atal'Jin; those devoted to the leader. These traitor elves were more specifically called those Devoted to Jin'thek. They were led by the White-Haired Wolf.