"The Priests of Rathma - or necromancers, as outsiders call them - have long remained shrouded in mystery," reads the official Blizzard description. "Deep within the jungles of Kehjistan, they train to preserve the delicate balance between the forces of life and death. Now Sanctuary has need of their unique power, and the Priests of Rathma will answer."
As a Necromancer, you'll be able to command armies of the dead, with the added bonus of being able to make corpses explode. Exploding corpses are basically all I ever wanted from videogames, to be honest.
Unlike Witch Doctors, Necromancers will command the flesh and all the grossness that entails. Drawing from the dark arts and probably Slipknot, the class will offer a more serious take on channelling lifeforce.
Blizzard say it's a reimagining of the classic Diablo 2 class, but not all Diablo 2 class skills will be returning. Check out some of the planned skills on Battle.net.
The class will release as part of the Rise of the Necromancer pack in 2017. In addition to unlocking the Necromancer as a playable character, players will also receive an in-game pet, two additional character slots, two additional stash tabs, a portrait frame, pennant, banner, and banner sigil.
You will need both Diablo 3 and Reaper of Souls to access this content.