When the Puncture altered the fundamental planar structure of Multiverse A, the Shadowfell was among the new arrivals to the multiverse. The Shadowfell overlaps the Material Plane and seems to roughly correspond to what used to be called the Plane of Shadow, in much the same way that the Feywild roughly corresponds to the old Ethereal Plane. Reliable paths to the Shadowfell are undiscovered or nonexistent, but it appears that proper ritual magic (such as that practiced by the Nameless Ones of Eberron) can transport a person bodily to the plane. Seth Mase has also visited the Shadowfell in his dreams while remaining bodily in the Material Plane, and Morden Mase and Rilla Tordeñas may have done this as well on the night of the Puncture.
Shadowfell scenery is dark, bleak, and twisted, but usually recognizable as analogous to that of the Material Plane it overlies. It is remarkable that the Shadowfell corresponds to planes that did not exist in the same multiverse as the Shadowfell prior to the Puncture. Another riddle concerns the correspondence of the Shadowfell, which is presumed to be a single plane, with the plural Material Planes.
The Shadowfell is inhabited by the shadar-kai, a race of dark-skinned humanoids who revere the Raven Queen. These shadar-kai claim that the souls of the dead travel through the Shadowfell under the Raven Queen’s auspices, and that she receives their souls.
Known cities of the Shadowfell include the Palace Duhr, near the Material Plane location of Shadowdale on Toril; Azartane, the Shadowfell analogue of Zaradene; and the Whitewood, the Shadowfell analogue of Qualinost. Other notable Shadowfell sites include the raven-haunted pyramid whose Material Plane ruins are known as the Hollow Temple.