David Wayne at Wayne's Retreat wants you to bring him the Lexicon Demonica.
You will need:
Recreating the enchantments on the blade requires several spells to be spoken in demonic.
It's not something I was taught during my training as an apprentice, but there's no way around it. There's a book, called the Lexicon Demonica, that will provide most of the words I need, but it's in the hands of a powerful Shadow Council warlock.
Deep in the halls of Auchindoun's Shadow Labyrinth, it is held by Grandmaster Vorpil. Do whatever you must to secure the book and bring it to me.
Have you retrieved the book?
<David leafs through the book's pages, shuddering.>
This is not something to be trifled with, <name>. After the weapon is created, I will destroy it. There is enough demonic power about in the world without this text out in the open.
This item only drops from the non-Heroic instance.