The Ancient Shadowmoon Spirit has used you as a pawn! Now that you have collected the items he required, he has revealed himself to be Teron Gorefiend. To break free of his possession, you must do his bidding and slay Karsius the Ancient Watcher.
If you succeed, return to Chief Apothecary Hildagard at Shadowmoon Village.
With Gorefiend's items restored, there is but one last piece to this puzzle: A host.
<The ancient shadowmoon spirit's lips curl up to form a wicked grin.>
Surely you did not believe the fairy tale that I told you. The Altar of Shadows is my prison. Without your help, I would have been stuck here for all eternity. Now, I will take over your body and you will destroy my captors and break these bonds. Refuse and we will both be stuck here forever.
Teron Gorefiend will be free!
You did what? FOOL!
You must right this wrong. After all, it is your fault. Take one of these helmets. They are each infused with the ever-burning ash that you retrieved for me. More importantly, they will allow you to see the ghosts of Shadowmoon, including Teron Gorefiend.
Should you ever find Teron Gorefiend, destroy him.