The Umbral, also called the Plane of Shadow, or the plane of decay, is a world in shades of gray, most color has been leached from the world, everything is dull and little color remains. The entirety of the senses are dulled and faded while on the Umbral.
Away from the crumbling cities of the Umbral are gray forests and deep fogs, faded stretches of brambles and murky swamps. The Umbral is dark and claustrophobic, oppressive by its very air.
The Umbral overlaps the Material Plane in much the same way as the plane of Faerie. Aside from the drab landscape, it appears similar to the Material Plane. Landmarks from the Material Plane are recognizable on the Umbral, but they are twisted and warped, distorted reflections of what exists on the Material Plane. Where a mountain stands on the Material Plane, the corresponding feature on the Umbral is a jagged rock outcropping that resembles a skull, a heap of rubble, or perhaps the crumbling ruin of a once-great castle. A forest on the Umbral is dark and twisted, its branches reaching out to snare travelers’ cloaks, and its roots coiling and buckling to trip those who pass by.
There are no Skylands in the Umbral, instead their positions are matched by hovering mounds of obsidian, that float suspended at the center of where the Skylands float in the material plane. The larger the Skyland in the material, the larger the chunk of black crystal in the skies of the Umbral.
Shadow dragons and undead creatures haunt this bleak plane, as do other creatures that thrive in the gloom, including cloakers and darkmantles. Few people travel willingly into the Umbral, but there are a few lost secrets hidden in the gloom, keys to ancient power and wisdom and potent magical items.
Shadow Crossings
Similar to Fey Crossings, Shadow Crossings are locations where the veil between the Material Plane and the Umbral is so thin that creatures can walk from one plane to the other. A blot of shadow in the corner of a dusty crypt might be a shadow crossing, as might an open grave. Shadow crossings form in gloomy places where spirits or the stench of death lingers, such as battlefields, graveyards, and tombs. They manifest only in darkness, closing as soon as they feel a touch of light.
In remote corners of the Umbral, it is easy to reach horrific demiplanes ruled over by accursed beings of terrible evil. These are creatures that seek the shadowfell to avoid the light, or that were imprisoned there by their rivals and enemies. The shades, lords of the shadowfell use these places as prisons for potential usurpers or powerful entities, such as Nakhotet, the vampire that turned Godwin Flamel and is believed to be the very first vampire.
These are dark places of horror and dread, places that have leeched between the planes through their dire influence and the astral travels of Orizon’s dreamers, spreading to become myths and stories of the dread beings that occupy these places.