Blizzard has announced another tie-in book for Diablo 3 , told from the perspective of Archangel Tyrael, is a guide to the action RPG universe."Here, in this illustrated and comprehensive tome, [Tyrael] reveals never-before-known secrets about the history of the world, the dark threats that yet face mankind, and his decision to join the ranks of humanity as a mortal," said Blizzard of the book.The mention of "dark threats" still ahead is interesting. Blizzard previously confirmed thatwill receive an expansion pack . Perhaps this book will give fans a peek at a few possible villains for this expansion?also contains writings from othercharacters, such as Leah and Deckard Cain. Deckard was previously featured in Book of Cain , another lore book released in late 2011. The family tree included inpresumably shows his fabled lineage.The 148-page book will be available starting on October 1st. It will set you back $39.99. You can check out the oh-so-angelic cover art below.