I've never found Blizzard particularly adept at storytelling, despite all the lore that's been established over the many years of the studio's existence. However, Diablo III: Reaper of Souls
mixes things up by giving us perhaps their most memorable and threatening villain since StarCraft
's Queen of Blades. I speak, of course, of Malthael, the titular Reaper. Once the Archangel of Wisdom, Malthael is consumed with hatred of demonkind, and the lengths to which he will go to destroy it include the annihilation of the human race. That's where you, the Nephalem, come in.
The exciting Act V brings you to a whole new level of dark; the doomed city of Westmarch might be the most threatening environment outside of a Souls game. Malevolent spirits are everywhere, and their constant presence will force you to think twice before passing corpses and inanimate objects. It's good, classic Diablo fun.