Underdark


 * This is an article on the Underdark setting. For the sourcebook, see Underdark (sourcebook).

The Underdark is the vast network of underground caverns and tunnels underneath the surface of Abeir-Toril. It is home to a host of evil beings driven deep into the caverns at the end of the age of demons.

Inhabitants
The Underdark is extremely dangerous, especially to those not native to it. There are the usual dangers associated with caverns: claustrophobia, occasional poor air circulation, and getting lost. There is no light except for occasional patches of fluorescent fungus; most Underdark inhabitants either have highly developed senses other than sight or have developed infravision. Food can be extremely difficult to find, and much of the natural vegetation is poisonous.

In addition to those dangers, the Underdark also is the home of many predators and often-hostile races, including:
 * Beholders
 * Derro
 * Drow
 * Duergar
 * Dwarves
 * Illithids
 * Kuo-toa
 * Svirfneblin

Domains
The Underdark is not one giant cavern under Faerûn, but rather, many giant networks of caverns and caves. As a result, it is not always possible to travel from one end of the Underdark to the other. The Underdark is divided into several domains that are similar to continents of the world above. While it is possible to travel from one place to another within a domain, seperate domains tend to have very few passages linking them. The major domains of the Underdark are:


 * The Buried Realms
 * The Darklands
 * The Deep Wastes
 * The Earthroot
 * The Glimmersea
 * Great Bhaerynden
 * The Northdark
 * Old Shanatar

Topography
The Underdark's underground landscape varies from small subterrean fisures nigh impossible for adventures to crawl through to wide expanses of deep water that hide coral caves, hollowed out sections of ice in which creatures live, and places where fungus, bones, or even pure force form "caves".

This varied landscape is as dynamic as the surface of Abeir-Toril. Some areas are even everchanging over the course of time by underground magmarivers, the emptying of underground lakes due to cracks in the rock formed by earthquakes. Due to this fact maps of the Underdark are highly unreliable.