Abyss

The Abyss is located at the deep heart of Durin. It is said that the dark god Kirbarir is imprisoned at the heart of this realm.
The Abyss is the home of various fiends, including devils, demons, and other creatures. There are many Realms within the Abyss, each a different hellish landscape ruled by one of the Dark Powers. Some scholars have described the Abyssal Realms as layers, but that is not entirely accurate. The Realms often connect to each other in strange ways, where one blasphemy bleeds into the next, defying conventional logic and cartography. There are a vast array of landscapes within the Abyssal Realms, including oceans, swamps, deserts, and unknown magical landscapes, but they are all connected by a lack of sunlight and a general sense of darkness. 
Notable realms include the Void of Igmakaran, the Stygian Library of Aezaya, the Swamp of Souls of Nhimbaloth, and the Sunless Depths of Icthyagron. The Void of Igmakaran is a seemingly endless expanse of darkness and nothingness. At the center of this shadowy realm lies the Sanctum of Igmakaran. The Stygian Library of Aezaya is also located in the Void. The Swamp of Souls feeds into the Sunless Depths, which lies both beside and beneath it.
The border between the deepest depths of the Underdark and the top layers of the Abyss are thin and permeable. The corruption of the Abyss slowly sinks into the Underdark, slowly corrupting all creatures who live there. Some scholars speculate that this corruption will eventually claim additional portions of the Underdark as layers of the Abyss.
Fiends from the Abyss can come to Durin in small numbers through the use of various summon spells. Larger fiendish forces are only able to enter Durin through powerful and complex rituals, which has only occurred twice in recent history: the Demonic Invasion and the end of the Vladkimiran Civil War. Powerful wizards are able to travel to the Abyss directly through the use of plane shift. Travelers can also go to the Abyss through portals located in the Underdark or within the Dead Lands.

Type

Abyss