Shadowfell

The Shadowfell, sometimes simply called Shadow, is a parallel plane from which necrotic energies and shadow magic stem. It exists as sort of a counterpart to Feywild in the sense that it is a reflection or "echo" of the Prime Material Plane except that it is a bleak, desolate place full of decay and death.

History
The Shadowfell was created in 1385 DR when Shar, having successfully killed Mystra, bound the energies of the Negative Energy Plane with the Plane of Shadow. Since then, the Shadowfell has existed as a center of Shar's power as well as a transitory place for dead mortals on their way towards judgment on the Fugue Plane.

Inhabitants
Much of the Shadowfell is a twisted reflection of the Prime Material plane and is populated primarily by dead creatures such as ghosts, spectors, and other undead who for whatever reason have refused to leave the Shadowfell and continue on to the Fugue Plane. There are however, numerous other inhabitants such as communities of Shadar-kai and Dark Ones who are both shadow creatures native to the Shadowfall