The Underdark
The Underdark was the vast network of underground caverns and tunnels underneath the surface of Abeir-Toril. It was home to a host of evil beings driven deep into the caverns at the end of the age of demons.Faerûn's Underdark includes drow cavern-cities, sunken aboleth strongholds, entire realms of mind flayers, and wondrous vistas shrouded in everlasting darkness.
The locales described here do not represent an exhaustive list of Underdark realms. Uncounted hundreds - perhaps even thousands - of deeply buried caverns and lightless cities exist beneath Faerûn, and virtually every surface-world dungeon seems to connect to murky depths from which all sorts of horrors can spew forth. Consider the places discussed in this section to be the ones the knowledgeable surface folk know of, and a sampling of the type of places that deep-delving heroes might explore.
An Underdark domain is something like a large island in the surface world. It may feature several distinct terrains and cultures, but it's possible to travel all over the island without having to set sail on the ocean. Similarly, two locales in a single domain are connected by enough cave systems, tunnels, and other passages to enable travel from one to the other without leaving the Underdark. Cities and settlements in the same domain are much more likely to engage in diplomacy, trade, or warfare than cities in separate domains. Like the continents or regions of the surface world, domains tend to group disparate cultures together and force them to interact with each other for good or ill.
Absence of light results in darkness. So, what results from the absence of Good? The Underdark is a place with very little of either.
- Mordenkainen
The locales described here do not represent an exhaustive list of Underdark realms. Uncounted hundreds - perhaps even thousands - of deeply buried caverns and lightless cities exist beneath Faerûn, and virtually every surface-world dungeon seems to connect to murky depths from which all sorts of horrors can spew forth. Consider the places discussed in this section to be the ones the knowledgeable surface folk know of, and a sampling of the type of places that deep-delving heroes might explore.
Underdark Domains
Faerûn's Underdark is not a single, contiguous cavern system, and even places on the same level may not connect to each other. The existence of Underdark settlements beneath Waterdeep, City of Splendors and Raven's Bluff, for example, does not mean it is possible to travel from one city to the other underground. In fact, the Underdark consists of a number of discrete domains. A domain is simply a collection of Underdark locales among which underground travel is reasonably easy. In certain places it may be possible to trail-blaze a route from one domain to another, but then again, it may not.An Underdark domain is something like a large island in the surface world. It may feature several distinct terrains and cultures, but it's possible to travel all over the island without having to set sail on the ocean. Similarly, two locales in a single domain are connected by enough cave systems, tunnels, and other passages to enable travel from one to the other without leaving the Underdark. Cities and settlements in the same domain are much more likely to engage in diplomacy, trade, or warfare than cities in separate domains. Like the continents or regions of the surface world, domains tend to group disparate cultures together and force them to interact with each other for good or ill.
Geography
The Underdark's underground landscape varied from small subterranean fissures almost impossible for adventurers to crawl through, to wide expanses of deep water that hid coral caves, hollowed out sections of ice in which creatures lived, and places where fungus, bones, or even pure force formed "caves."
This varied landscape was as dynamic as the surface of Abeir-Toril. Some areas were always changing over time because of underground magma rivers or the emptying of underground lakes due to cracks in the rock formed by earthquakes. This meant maps of the Underdark were highly unreliable.
The catastrophe was known as Rockfire took place many dwarven generations before the "discovery" of Maztican continent by Amn. The calamity was caused by uncontrolled magics of the Darkfyre harnessed by the drow. It left Underdark beneath Maztica believed to be uninhabitable, filled with poisonous gas and molten rock. The dwarves who became cut off from Faerûn, with passing centuries became desert dwarves who lived in shallow caves close to the surface of the House of Tezca dessert. They believed that the Rockfire completely exterminated the drow and the rest of the dwarves. However that was proven to be a false belief by the mid-14th century DR. The Underdark passages between the two continents were believed to be lost legends, gone, and forgotten by inhabitants of Faerûn.
This varied landscape was as dynamic as the surface of Abeir-Toril. Some areas were always changing over time because of underground magma rivers or the emptying of underground lakes due to cracks in the rock formed by earthquakes. This meant maps of the Underdark were highly unreliable.
Maztica
The Underdark burrowed deep under the Trackless Sea, stretching between the continents of Maztica and Faerûn. Ancient dwarven legend talked about a great ancient war between the stout folk and the drow that raged in the depths underneath the Trackless Sea. The war was ended by drow magics that lit the tunnels with fires so hot they melted rock and flooded the portion of the Underdark that connected dwarves and drow who resided in Maztican Underdark with their eastern kin.[7]The catastrophe was known as Rockfire took place many dwarven generations before the "discovery" of Maztican continent by Amn. The calamity was caused by uncontrolled magics of the Darkfyre harnessed by the drow. It left Underdark beneath Maztica believed to be uninhabitable, filled with poisonous gas and molten rock. The dwarves who became cut off from Faerûn, with passing centuries became desert dwarves who lived in shallow caves close to the surface of the House of Tezca dessert. They believed that the Rockfire completely exterminated the drow and the rest of the dwarves. However that was proven to be a false belief by the mid-14th century DR. The Underdark passages between the two continents were believed to be lost legends, gone, and forgotten by inhabitants of Faerûn.
Climate
The Underdark's environment varied vastly from the surface world, making adventuring through it a dangerous expedition. Just like trekking through a desert, adventurers traversing the Underdark's passages needed to be well prepared.
The Underdark was mainly without any source of light save for the occasional luminous rocks or fungi. Large portions of it were also without food or water, making well-stocked food supplies a must-have when exploring uncharted terrain underground.
Lack of light combined with a tomb-like silence made traveling something only for the strong-hearted. The nerve-wracking silence made even experienced adventurers grow agitated after a few days.
Just like deep dungeons, the air could grow stale and even poisonous in the Underdark. It could contain explosive gases from underground volcanic activity or other deadly gases bubbling out of deep fissures in the rock. Bad air and poisonous fumes could collect in portions of tunnels and caves more or less isolated from the main vaults and caverns. Siphon-like tunnels holding water could also trap these gases for a long time.
The temperature underground varied according to depth and the proximity of thermal activities in the area. Throughout the year, the temperature remained stable and moderate in most regions, usually slightly clammy or chilly. The water underground was extremely cold and posed a hypothermia risk.
The Underdark was mainly without any source of light save for the occasional luminous rocks or fungi. Large portions of it were also without food or water, making well-stocked food supplies a must-have when exploring uncharted terrain underground.
Lack of light combined with a tomb-like silence made traveling something only for the strong-hearted. The nerve-wracking silence made even experienced adventurers grow agitated after a few days.
Just like deep dungeons, the air could grow stale and even poisonous in the Underdark. It could contain explosive gases from underground volcanic activity or other deadly gases bubbling out of deep fissures in the rock. Bad air and poisonous fumes could collect in portions of tunnels and caves more or less isolated from the main vaults and caverns. Siphon-like tunnels holding water could also trap these gases for a long time.
The temperature underground varied according to depth and the proximity of thermal activities in the area. Throughout the year, the temperature remained stable and moderate in most regions, usually slightly clammy or chilly. The water underground was extremely cold and posed a hypothermia risk.
Fauna & Flora
The Underdark was extremely dangerous, especially to those not native to it. There were the usual dangers associated with caverns: claustrophobia, occasional poor air circulation, and getting lost. There was no light except for occasional patches of fluorescent fungi; most Underdark inhabitants either had highly developed senses other than sight or had developed darkvision. Food could be extremely difficult to find, and much of the natural vegetation was poisonous.[citation needed]
In addition to those dangers, the Underdark was also the home of many predators and often-hostile races, including aboleth, beholders, cloakers, derro, drow, duergar, dwarves, illithids, kuo-toa, driders, and svirfneblin.
Plant life and animal life could be as varied underground as on the surface. Ranging from small insects to hook horrors or shadow dragons, which set up their realms deep down, everything could be expected. Plant life was unable to utilize sunlight as a source for energy, and thus took on strange forms adapted to life underground. Many fungi were also found underground. Being unable to digest normal nutrients most of the time, they relied on absorbing faerzress for their energy.
Some dangerous flora of the Underdark were the exploding bibberbangs.
In addition to those dangers, the Underdark was also the home of many predators and often-hostile races, including aboleth, beholders, cloakers, derro, drow, duergar, dwarves, illithids, kuo-toa, driders, and svirfneblin.
Plant life and animal life could be as varied underground as on the surface. Ranging from small insects to hook horrors or shadow dragons, which set up their realms deep down, everything could be expected. Plant life was unable to utilize sunlight as a source for energy, and thus took on strange forms adapted to life underground. Many fungi were also found underground. Being unable to digest normal nutrients most of the time, they relied on absorbing faerzress for their energy.
Some dangerous flora of the Underdark were the exploding bibberbangs.
Maps
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The Underdark
Type
Underground / Subterranean
Included Locations
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