The Tablet tells much.  But not enough!  Not nearly enough!$B$BThere is a book, a digest that Yagyin wrote in ages past.  The ... people I fled ... they keep this book in many places.  And their most learned study it.  It holds vast knowledge.  Knowledge to protect us!$B$BGo to Gerrig Bonegrip.  He is in a shop in Ironforge, in the Forlorn Cavern.  Show him this sigil and he'll think you one of them.  Ask him for Yagyin's Digest ... and bring it to me!