Reaper of Souls is the first expansion for Diablo III. The plot from Reaper of Souls starts the fifth act of the main game. After Diablo's defeat, Tyrael and the Horadrim set to hide the Black Soulstone containing his essence in heaven, but the Angel of Death, Malthael, took it from them to use it fro his own agenda. Upon Tyrael's request, the Hero will travel to Westmarch to confront Malthael and his reaper army.
This expansion introduces a new class, the heavy-armored Crusader and allows the characters to go above level 60, up to level 70, and learn new skills. The forge and jewelry can now be upgraded further, and the same goes for the stash, that can have more tabs. The expansion also introduces a new artisan, the Mystic, who can transmogriphy equipment by changing a weapon or armor piece's abilities and looks. New game modes are now available:
Adventure Mode: the player can now travel to any location from the game via the waypoints
Bounties: missions taken on behalf of the Horadrim, to gain various treasures and rift keystones that give access to another realm
Nephalem Rifts: endless randomized dungeons that will challenge the player and yield many rewards