Shadowfell

The Plane of Shadow was one of the planes of existence in various cosmological models. Its purpose and characteristics evolved as new cosmologies were formulated. Other names for this plane included Shadowland, the Demi-Plane of Shadow, the Shadowfell, and simply Shadow. "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."

- Manual of the Planes

Shadow Plane in the Great Wheel Model
When the Great Wheel cosmology was in vogue, the Plane of Shadow was considered only a demiplane. Demiplanes formed out of the proto-matter that ebbed and flowed about the Ethereal Plane, creating a finite plane with its own Border Ethereal whenever a critical mass was achieved. The largest of these was called the Demiplane of Shadow, and was made up of both positive and negative energy in equal measure. For those traveling through the Ethereal Plane, the curtain of vaporous color for the Demiplane of Shadow was the color silver. Wizards could shadow walk directly to the edge of the Shadow Plane and travelers could use this plane as a transitive plane to traverse many Prime Material miles/kilometers very quickly. If any were brave enough to cross the Demiplane of Shadow, it was possible to find the borders of other planes of reality.

Very little was known about the Shadow Plane other than it was a dim and dismal place, home to a mysterious form of undead called shadows, other "shadow" creatures such as the shadow mastiff and shadow dragon, and a race of humanoids known as shades. The material of the Shadow Plane could be manipulated by illusionists to form semi-real monsters and quasi-real evocations that were still effective (to a lesser degree) even if the target successfully disbelieved the illusion.

Shadow Plane in the World Tree Model
When the World Tree cosmology model was introduced, the Plane of Shadow was upgraded to an infinite plane that coexisted with the Prime Material Plane&mdash;touching it at all points and having the same basic geography &mdash;but only accessible at night or from shady areas using the shadow walk spell. Naturally occurring intermittent portals called vortices appeared between this plane and the Material Plane in seemingly random areas of heavy shade or darkness. The entry and exit point of a vortex were unpredictable as was their duration, lasting a few days at most. The Plane of Shadow was no longer connected to the Ethereal Plane, even though it was coexistent with it. Rapid movement between points of the Prime were still possible by stepping into the Shadow Plane and skirting the edge before stepping back into the Prime, but arriving at a particular destination was much less precise than before. Intrepid travelers could still reach other universes by traversing the Shadow Plane and locating the border with an alien world such as Oerth for example.

Description
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". Sources of illumination only penetrated half as far as normal, flames and fires put out less heat, and spells that dealt with light or fire were less predictable and prone to failure. Shadow spells on the other hand, were enhanced.

Gravity and time were the same on the Shadow Plane as on the Prime, but because the Shadow Plane was magically morphic (and divinely morphic in the realms of Shar and Mask) the landscape was a twisted echo of what existed on the Prime. 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 Shadow Plane 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.

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 (sixty meters) 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 Shadow Plane 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 Negative Energy Plane and life-draining undead such as shadows, ghosts, and vampires. These "darklands" had a minor negative-dominant trait and unprotected visitors immediately felt the life force being sucked from their bodies&mdash;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 Shadow Plane.

Other less dangerous but quite unsettling echoes occurred in areas analogous to towns and cities in the Prime Material Plane. They were nothing more than mirages, but familiar faces and places seen through the macabre mirror of the Shadow Plane 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. Over time however, 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.

Inhabitants
Probably the most dominant race of beings on the Plane of Shadow were the shades&mdash;ancestors of ancient Netherese humans who resided on the plane in their floating city for centuries and acquired many abilities from immersion in shadow essence. Malaugryms may have been superior to shades, having the advantage of being shapeshifters and practically immortal unless killed in some fashion; but their small numbers, fierce independence, and difficulty in mastering interplanar travel made them much less organized and effective.

Other creatures that were either native to the plane or attracted to it included bodaks, cloakers, darkweavers, ephemera of all kinds, liches, nightshades, shadar-kai, undead shadows,  shadow dragons, shadow mastiffs,  shadurakul, spectres, and wraiths. Occasionally, animals and monsters would wander or fall into a vortex to the Shadow Plane and become trapped there. Those that survived eventually took on shadow-given abilities, carved out a niche in the ecosystem, and preyed on whatever attracted their attention. Examples included apes, basilisks, bears, owlbears, rats, umber hulks, and wolves. Such creatures could give rise to dark creatures, shadowy counterparts of natural creatures.

Realms
Only two deities were known to have claimed the Plane of Shadow as their home:
 * Mask, the Master of all Thieves and Lord of Shadows had a realm on this plane called Shadow Keep. It was made out of shadowstuff and was extremely difficult to see even when standing right next to it.
 * Shar, Mistress of the Night and Lady of Loss, once resided in a high tower called the Palace of Loss. It had no apparent means of entry or exit, but her followers had no trouble gaining access. She sometimes kept prisoners there so she could enjoy their suffering. After the Spellplague, she moved her abode to the Towers of Night and left behind a deep dark hole guarded by evil creatures. This Foundation of Loss exuded palpable grief and was reported to contain a portal to her home in the Towers of Night.

Origin
The special and unique nature of this plane caused not only cosmologists to speculate about its origins, but visitors and planar travelers as well. Some believed the Plane of Shadow spontaneously formed as a demiplane out of the Ethereal Plane. Others believed that it was created by the primordials as an echo of the Prime Material Plane. But most cosmologists and planeswalkers with a sense of adventure liked to talk about the legend of the Shining Citadel. Briefly, the legend postulated that the Plane of Shadow was once bright and colorful like the Material Plane, but at some point in the distant past a mysterious group who worshiped the plane's creator took all of the light, color, and most of the life-force from the rest of the plane and concentrated it into a mighty citadel. One would think that a structure containing most of the energy from an entire plane of existence would be hard to miss, but no one has ever found the Shining Citadel, except perhaps, as the legend states, those who venture into the deepest parts of the Plane of Shadows and never return.

History
The Plane of Shadow had a significant share of influence on the peoples and events of the Prime Material Plane. Some notable historic happenings: &mdash;A rift to the Shadow Plane is opened in the skies over Sembia and the city of Ordulin is destroyed when a shadowy tract of land falls on it.
 * Circa -3500 DR, in the Late period of ancient Imaskar: Archwizard Madryoch the Ebon Flame attempted to use the power of the Shadow Plane to overthrow Lord Artificer Omanond.
 * -2954 DR: The gloaming city of Sphur Upra is founded on the Shadow Plane.
 * -533 DR, the Year of Plentiful Wine: The Shadow Plane is rediscovered by the Netherese and their wizards begin to study it.
 * -339 DR, the Year of Sundered Webs: The floating city of Thultanthar makes a complete transition into the Plane of Shadow before the Fall of Netheril.
 * -221 DR, the Year of Shambling Shadows: Shadow dragons take the drow city of Chaulssin, beginning that city's inexorable transition into the Shadow Plane.
 * 534 DR, the Year of the Spitting Viper: The city of Sphur Upra crosses over and exists in equal parts on both the Shadow Plane and the Material Plane.
 * 734 DR, the Year of the Splendid Stag: The inhabitants of Chaulssin retreat to the Plane of Shadow ahead of an invasion by forces from Menzoberranzan, leaving the city swarming with shadow creatures.
 * 1179 DR, the Year of the Stalking Satyr: Arunsun Tower is attacked by malaugrym but they are repelled by Khelben Arunsun, Elminster, and a cadre of Waterdhavian wizards.
 * 1182 DR, the Year of the Tomb: Marks the first conflict of the Harpstar Wars between the Harpers and the malaugrym.
 * 1372 DR, the Year of Wild Magic: Thultanthar, the floating city now renamed "Shade", returns to Toril and hovers over a spot in the Anauroch desert called the Scimitar Spires.
 * 1374 DR, the Year of Lightning Storms: Sharran and Cyricist cultists based in the Shadow Swamp on the Plane of Shadow, plotting to tear apart the Weave from the Black Rift. Adventurers pursue and disrupt their efforts, and find the Black Chronology among their detritus.

Shadow Plane in the World Axis Model
In 1385 DR, the Year of Blue Fire, Shar succeeded in engineering the murder of Mystra by Cyric, plunging the multiverse into years of upheaval and chaos called the Spellplague. The Elemental and Energy Planes collapsed into the Elemental Chaos but not before Shar managed to manipulate some of the necrotic energies from the Negative Energy Plane and inject it into the Plane of Shadow. Such was the power of this combination that the souls of the dead began to be drawn to this altered plane and had to pass through it before reaching their final judgment on the Fugue Plane. Shar called her new creation the Shadowfell.

Appearances

 * Adventures:
 * Cormyr: The Tearing of the Weave: Adventurers pursue cultists of Shar and Cyric through the Dusk Lord's Passage to the Shadow Swamp, disrupting their plots there.
 * Video games:
 * Baldur's Gate: Dark Alliance: In 1235 DR, the Black Horde attacked Faerûn. The Horde defeated Eldrith the Betrayer, who would go on to betray Baldur's Gate. They killed her and she was reborn out of hatred. In her soul of hatred, the Onyx Tower was created and tied to her life. The Onyx Heart was located in the Plane of Shadow and only with its destruction could the Onyx Tower be destroyed.
 * Baldur's Gate: Dark Alliance II: In 1376 DR, eight brave heroes ventured into the Plane of Shadow and defeated one of its guardians, Mordoc SeLanmere and destroyed the Onyx Heart.
 * Neverwinter Nights: Shadows of Undrentide: The Hero escapes impending doom by traveling to the Plane of Shadow using a magic mirror.
 * Neverwinter Nights 2: Mask of the Betrayer: Travel between the Shadow Plane and Prime Material Plane is possible in certain places in Mulsantir at certain times of day. Shadow Mulsantir contains a Temple of Myrkul, in the place where a Shrine to Kelemvor stands on the Prime. Within this temple is found a portal leading to Kelemvor's domain, the Fugue Plane.