The Addon Diablo 3: Reaper of Souls requieres a full version of Diablo 3 in order to be played.
No One Can Stop Death
The lords of hell rage within the Black Soulstone, their souls screaming for vengeance and release. Before the artifact can be sealed away forever, Malthael–Angel of Death–manifests in the mortal realms with a deadly new purpose: to steal the Black Soulstone and bend its infernal power to his will.
So begins the end of all things...
