Plagueland

Plaguelands (also called changelands ) were unnatural areas or regions in Faerûn where pockets of Spellplague persisted after the Wailing Years.

After the Second Sundering, most plaguelands returned to normality as the effects of the Spellplague ceased to be.

Description
Plaguelands were shrouded by a luminous, liquid blue fog, and the surrounding terrain was sharp-edged and clear. Inside the plagueland, the land was mutable, like boiling mud. Earthmotes were common across the terrain, as well as immense zones of blue fire. In those regions, reality was in flux, and all features, such as the terrain and the sky, were somehow mixed, forming an alien landscape.

Underground, such as in the Underdark, plaguelands often took the form of enclosed pockets of active Spellplague, often called plaguecaves. In these spaces, the laws of physics appeared broken, with water flowing in streams through the air or falling upward, motes of rock drifting in space, and the caves and tunnels themselves twisting and warping with time.

Creatures that ventured close or into the plaguelands could gain spellscars or be transformed into plaguechanged horrors. The Order of Blue Flame often sought out plaguelands in what were referred to as Scar Pilgrimages. The Abolethic Sovereignty was also interested in study, cultivate, and expand existing plaguelands.

Locations
As of 1479 DR, the largest plagueland was the Plaguewrought Land, located in Interior Faerûn, south of the Vilhon Wilds. There were also plaguelands in the Yuirwood, in Halruaa and nearby regions, in Elturgard, in Erlkazar, in Sumbar, near Evermeet, and in the Hordelands, above Deep Imaskar. Tilverton Scar, in Cormyr, was also considered a plagueland.

In Laerakond, the only known plaguelands were the Glaur Barrens in Gontal.

In the Underdark, the known plaguelands were located in Brikklex, near Deep Imaskar, in the cavern that once held Oaxaptupa in Old Shanatar, and at the Cauldron of Blue Fire below Neverwinter.