Bring the the Carapace of the Old God, 2 Idols of the Sage, 5 Silver Scarabs and 5 Bone Scarabs to inside Ahn'Qiraj. You must also attain Honored reputation with the Brood of Nozdormu to complete this quest.
You will need:
When the stars are favorable, he will lash out against all living beings with terrible wrath. You must find him before then and find a way to bring his existence to an end.
Do this and bring me a piece of his husk. I shall grant you armor no mortal has ever worn... armor fit for one who has slain a god!
You will receive: