The year is 1285, and in the aftermath of the Prime Evils and the Lesser Evils raging across Creation, Sanctuary is attempting to rebuild itself. With Diablo destroyed, the forces of Hell are in disarray with no hierarchy or concrete leadership. While there are still rifts through which Hell can enter Sanctuary, they are more like warbands organized under powerful demons as opposed to concentrated invasion forces like they were during the large wars against the High Heavens.
The Nephalem and the High Heavens have just begun to form and feel out their alliances against the forces of the Burning Hells while the world starts to reorganize itself. Many portions of Sanctuary are still corrupted and touched by darkness, but many more are being made habitable by people pushing back against the corruption.
The world consists of three planes: Sanctuary, where the humans live and make their homes. The High Heavens, where the Angels and beings of light have long waged war against the darkness from. And finally, the Burning Hells, presently in turmoil from a lack of present leadership and direction.