Tanglebriar
The Tanglebriar is a vast swamp in southern Kyonin, wedged between the Fierani Forest to the north and the Five Kings Mountains to the south. Although technically within the borders of Kyonin, it has become the largely uncontested domain of the demon lord Treerazer since he was driven there by the returning Sovyrian elves in 2632 AR. The realm grows ever more in appearance like Treerazer's lost Abyssal home.
The elves of Kyonin have worked for centuries to contain the spreading taint of the Tanglebriar. For now, the elves have succeeded in containing the threat.
Geography
Demons of note
The glabrezu demon Mokravud is one of Treerazer's lieutenants, and unusually for his type, practices great patience and subtlety when targeting his victims. He has served the Lord of the Blasted Tarn for centuries, and prefers going after select elven officers, rather than decimating entire platoons.Fauna & Flora
The Tanglebriar is a dark and twisted swamp, haunted by demons and creatures corrupted by centuries of the demon lord's foul influences. Trees block out the sun and plants have taken on a decidedly hostile appearance and nature. True to its name, thick patches of nettles and prickly briers cover the swamp, interspersed with poisonous fungi and mold.
In addition to the ubiquitous demons (primarily hezrou, glabrezu, babaus, and nalfeshnee) which can be found roaming the swamp individually or in small gangs looking for their next victim, Tanglebriar is also home to other sinister creatures. These include dark fey, fiendish vermin grown to alarming size, evil cultists from all over who bring supplies and news of the outside world to Treerazer, and carnivorous fungi (ascomoids, basidironds, violet fungi, and phycomids).
The Tanglebriar is also home to several small tribes of orcs who devoutly worship Treerazer. These orcs compensate for their comparative lack of numbers and the lesser status of their chosen god by being exceptionally violent and vicious, even by orc standards.