Shadowfell

"It is the toxic plane of darkness and power. It is the hidden place that hates the light.

It is the frontier of worlds unknown."

The most striking and immediate impression a visitor to the Plane of Shadow experienced was the lack of color and light; no sun, moon, or stars adorned the vault of the inky black sky, and all things looked as if the color had leeched out, leaving nothing but black and white, which in the dimness were more like "dark black" and "light black". A light source only illuminated half the distance it normally would, flames and fires put out less heat, and spells that dealt with light or fire were less predictable and prone to failure, whereas shadow spells were enhanced. On the other hand, although it would not illuminate as far, any light source on the plane could be spotted at a distance of up to ten times its normal range of illumination, such was the contrast to the constant gloom, similar to a star in the night sky. Even a light source that only put out shadowy illumination, like a darkness spell or a lantern burning shadowlight oil could be seen up to five times its range of illumination.

Gravity and time were the same on the Shadowfell as on the Material Plane, but the landscape was a dark, twisted echo of what existed on the Material Plane. Upon entering the Plane of Shadow, the local features were usually quite similar: casting shadow walk in a forest put you in a shadow forest; casting it under water dropped you in a similar body of water, etc. But from that starting point, the landscape diverged rapidly away from the familiar, and on subsequent visits from the same starting point it diverged in different ways, making mapping the Shadowfell a useless endeavor.

Landmarks were usually recognizable but altered in some bizarre way: buildings might be constructed in a different style, built with different materials, at a different location, and/or in any condition from dilapidated ruins to its normal appearance, for example, or otherwise strange and distorted. Similar sites were sometimes called "shadow-analogues".

Due to the ever-changing landscape, the Plane of Shadow was subject to relatively frequent but very small earthquakes (called shadow quakes) that resembled an earthquake spell in an area about two hundred feet in diameter. For those on the ground, damage was equivalent to a Prime earthquake, but shadow quakes could also disrupt the shadow walk spell and dump unfortunate travelers onto the Shadowfell in the middle of the disturbance at a place very likely unknown and far from their destination.

Some areas on the Plane of Shadow seemed to have an affinity with the life-draining undead such as shadows, ghosts and vampires. These "darklands" were unprotected and visitors immediately felt the life force being sucked from their bodies—unless they exited the darkland quickly, all that was left of them was a pile of ash. Someone with protection from negative energy could stop and admire the utter desolation in an otherwise forlorn landscape, and perhaps make the acquaintance of the truly inimical undead.

Thankfully, no natural vortices opened into darklands regions, preventing the unwary from stepping through into almost certain death, and keeping the creatures that thrived there from having easy access to other planes. Material Plane locations such as desecrated burial mounds, haunted battlefields, and necromantic foci frequently had a darkland echo on the Shadowfell.

Other less dangerous but quite unsettling echoes occurred in areas analogous to towns and cities in the  Material Plane. They were nothing more than mirages, but familiar faces and places seen through the macabre mirror of the Shadowfell could be very demoralizing. Structures might appear altered, dislocated, destroyed, or replaced entirely by something else. Mirages of the living had visages of distorted nightmares, but were still recognizable enough to give travelers a jolt of fear and revulsion.

Air, water, and food existed on this plane, supporting plants, animals, and some humanoids adapted to the shadow environment. Visitors could survive indefinitely if they were willing to endure thick, foul-smelling water, food that oozed dark blood, and a pervasive nip of cold in the air. A visitor could never feel warm, would often hear or sense the presence of things that weren't there, and could never shake the feeling of being watched. It was a constantly unsettling place. Over time, exposure to the Plane of Shadow altered living things, increasing various traits and abilities but also some vulnerabilities. Emotions and the ability to experience them seemed to fade over time for those imbued with shadowstuff.

Shar rules the Shadowfell from the 'Black Spire', a fortress only accessible to those she allows.