This quest is not available in game.
Kilix the Unraveler in the Pit of Narjun has tasked you with defeating Anub'arak in Azjol-Nerub. You are to return to Kilix with Anub'arak's Broken Husk.
Anub'arak, the traitor king, makes his home in the once proud underland of Azjol-Nerub.
Since his betrayal, he has twisted and perverted our homeland into the wretched squalor it is today. He rules over an army of undead nerubians who, like their leader, have pledged themselves to serving the Lich King.
Bring an end to the traitor king's reign, <class>. You will be doing a great service to both of our peoples.
If you manage to succeed where all others have failed, bring me the husk of Anub'arak.