Assault on Violet Hold: The Fel Lexicon

I have been studying the language of the demons, but it has been difficult to get my hands on written material. I have heard rumor of a book called the Fel Lexicon, written by an ancient scholar who spoke both eredun and draenei. If I could just get my hands on that book, I could learn so much! I heard that this book might be in the hands of a powerful prisoner inside the Violet Hold. Bring me this book, and my work here will go much faster.