As the days get darker, it might be time to let your tabletop RPG sessions do the same. The Humble RPG Book Bundle: Warhammer 40K: Black Crusade & Only War is out now. Featuring a huge collection of RPG books from Cubicle 7 set in the Warhammer 40k universe. Starting at just $1, you'll be able to get your hands on some of the best, darkest RPG books on the market.