Diablo III Book of Cain

"In Blizzard Entertainment's Diablo and Diablo II, Deckard Cain delivered quests, accompanied the brave adventurer and, as the last of the Horadrim, provided a link to the greater history of the world of Sanctuary. Ever mysterious during these appearances, Cain hinted at a larger story, providing snippets of it in his notebook. Designed as an 'in-world' artifact from the Diablo universe, Diablo III: Book of Cain includes Cain's revealing meditations, as well as dozens of sketches and color artworks depicting the angelic and demonic beings who wage constant war with one another."