Travel to the Wyrmbog in Dustwallow Marsh and seek out Emberstrife's Den. Once inside, wear the Amulet of Draconic Subversion and speak with Emberstrife.
I have attuned this medallion with the magic necessary to create and maintain an illusion within the bounds of the den of Emberstrife.
Emberstrife is an ancient drake; an old gatekeeper of Nefarian, burdened with the duty to test those dragonspawn that would ascend to the rank of elite guard to Onyxia.
Travel to the Wyrmbog of Dustwallow Marsh and enter the lair of Emberstrife. Once there, put on the amulet and follow where your destiny may lead!