Underdark
The Underdark, also known as Deepearth, the Lightless Lands, the Night Below, or the Realms Below,<sup> [\[1\]](#cite_note-DDGttU-p7-1)</sup> was the enormous system of subterranean caves, caverns, and tunnels located beneath the surface of [Abeir-Toril](https://forgottenrealms.fandom.com/wiki/Abeir-Toril "Abeir-Toril").<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup> <sup> [\[4\]](#cite_note-UD-p4-4)</sup>
Like many natural formations on the Material Plane, the Underdark had counterparts in the [Feywild](https://forgottenrealms.fandom.com/wiki/Feywild "Feywild") and the [Shadowfell](https://forgottenrealms.fandom.com/wiki/Shadowfell "Shadowfell"). In the Feywild, there existed the [Feydark](https://forgottenrealms.fandom.com/wiki/Feydark "Feydark" In the Shadowfell, there existed the [Shadowdark](https://forgottenrealms.fandom.com/wiki/Shadowdark "Shadowdark").
“
Absence of light results in darkness. So, what results from the absence of [Good](https://forgottenrealms.fandom.com/wiki/Good "Good")? The Underdark is a place with very little of either.
”
— Mordenkainen<sup> [\[5\]](#cite_note-MToF-pp189-5)</sup>
[1 Geography](#Geography) - [1.1 Domains](#Domains)
[2 Topography](#Topography) - [2.1 Maztica](#Maztica)
- [2.2 Laerakond](#Laerakond)
[3 Environment](#Environment)
[4 Climate](#Climate)
[5 Inhabitants](#Inhabitants)
[6 Ecology](#Ecology)
[7 Appendix](#Appendix) - [7.1 See Also](#See_Also)
- [7.2 External Links](#External_Links)
- [7.3 Gallery](#Gallery)
- [7.4 Further Reading](#Further_Reading)
- [7.5 References](#References)
[World Above](https://forgottenrealms.fandom.com/wiki/World_Above "World Above"): The name that those who lived in the Underdark gave the surface area of [Toril](https://forgottenrealms.fandom.com/wiki/Toril "Toril").<sup> [\[6\]](#cite_note-FRCG-p218-6)</sup>
[Upperdark](https://forgottenrealms.fandom.com/wiki/Upperdark "Upperdark"): The first 3 miles (4.8 kilometers) below the surface. It was here where the surface dwellers and those in the Underdark most often met.<sup> [\[6\]](#cite_note-FRCG-p218-6)</sup>
[Middledark](https://forgottenrealms.fandom.com/wiki/Middledark "Middledark"): Located 3 to 10 miles (4.8 to 16 kilometers) below the surface, this layer was where most of the Underdark cities were located.<sup> [\[6\]](#cite_note-FRCG-p218-6)</sup>
[Lowerdark](https://forgottenrealms.fandom.com/wiki/Lowerdark "Lowerdark"): 10 miles (16 kilometers) or more below the surface, the Lowerdark was where even those who knew the Underdark were loath to go.<sup> [\[6\]](#cite_note-FRCG-p218-6)</sup>
The Underdark was not one giant cavern under [Faerûn](https://forgottenrealms.fandom.com/wiki/Faer%C3%BBn "Faerûn"), but rather many huge networks of caverns and caves. As a result, it was not always possible to travel from one end of the Underdark to the other. The Underdark was divided into several domains that were similar to continents of the world above. While it was possible to travel from one place to another within a domain, separate domains tended to have very few passages linking them. The major domains of the Underdark were the [Buried Realms](https://forgottenrealms.fandom.com/wiki/Buried_Realms "Buried Realms"), the [Darklands](https://forgottenrealms.fandom.com/wiki/Darklands "Darklands"), the [Deep Wastes](https://forgottenrealms.fandom.com/wiki/Deep_Wastes "Deep Wastes"), the [Earthroot](https://forgottenrealms.fandom.com/wiki/Earthroot "Earthroot"), the [Glimmersea](https://forgottenrealms.fandom.com/wiki/Glimmersea "Glimmersea"), [Great Bhaerynden](https://forgottenrealms.fandom.com/wiki/Great_Bhaerynden "Great Bhaerynden"), the [Northdark](https://forgottenrealms.fandom.com/wiki/Northdark "Northdark"), and [Old Shanatar](https://forgottenrealms.fandom.com/wiki/Old_Shanatar "Old Shanatar").<sup> [\[7\]](#cite_note-UD-p122-126-7)</sup>
[
](https://static.wikia.nocookie.net/forgottenrealms/images/f/f2/Drizzt%27s_Underdark_Map.jpg/revision/latest?cb=20230815055616)
_A map of the Underdark beneath western Faerûn._
The Underdark's underground landscape varied from small subterranean fissures almost impossible for adventurers to crawl through to more conventional caves and caverns. But there were also wide expanses of deep water in which coral caves grew, blocks of ice that creatures hollowed out and dwelt inside, and cave-like spaces within masses of fungus or bone or else supported by bubbles of magical [force](https://forgottenrealms.fandom.com/wiki/Force "Force").<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup> <sup> [\[8\]](#cite_note-UD-p100-8)</sup>
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.<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup> <sup> [\[8\]](#cite_note-UD-p100-8)</sup>
The Underdark burrowed deep under the [Trackless Sea](https://forgottenrealms.fandom.com/wiki/Trackless_Sea "Trackless Sea"), stretching between the continents of [Maztica](https://forgottenrealms.fandom.com/wiki/Maztica "Maztica") and Faerûn. Ancient [dwarven](https://forgottenrealms.fandom.com/wiki/Dwarf "Dwarf") 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 the Maztican Underdark with their eastern kin.<sup> [\[9\]](#cite_note-IH-p61-9)</sup> In fact, the catastrophe was known as [Rockfire](https://forgottenrealms.fandom.com/wiki/Rockfire "Rockfire") and took place many dwarven generations before the "discovery" of Maztican continent by [Amn](https://forgottenrealms.fandom.com/wiki/Amn "Amn"). The calamity was caused by uncontrolled magics of the _[Darkfyre](https://forgottenrealms.fandom.com/wiki/Darkfyre "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](https://forgottenrealms.fandom.com/wiki/Faer%C3%BBn "Faerûn"), with passing centuries became [desert dwarves](https://forgottenrealms.fandom.com/wiki/Desert_dwarves "Desert dwarves") who lived in shallow caves close to the surface of the [House of Tezca](https://forgottenrealms.fandom.com/wiki/House_of_Tezca "House of Tezca") desert. 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–14<sup> th</sup> century DR.<sup> [\[10\]](#cite_note-IH-p269-10)</sup> The Underdark passages between the two continents were believed to be lost legends, gone, and forgotten by inhabitants of Faerûn.<sup> [\[9\]](#cite_note-IH-p61-9)</sup>
_Main article: [Abeiran Underdark](https://forgottenrealms.fandom.com/wiki/Abeiran_Underdark "Abeiran Underdark")_
When the [Spellplague](https://forgottenrealms.fandom.com/wiki/Spellplague "Spellplague") brought the continent of [Laerakond](https://forgottenrealms.fandom.com/wiki/Laerakond "Laerakond") to Toril, it also brought a part of the [Abeiran Underdark](https://forgottenrealms.fandom.com/wiki/Abeiran_Underdark "Abeiran Underdark") below it. It was different from the Underdark of Faerùn, but besides that it was inhabited by drow and mysterious monsters, little was known about this region.<sup> [\[11\]](#cite_note-Dra366-p52-11)</sup>
[
](https://static.wikia.nocookie.net/forgottenrealms/images/f/fe/Underdark_3e_map.jpg/revision/latest?cb=20240913122904)
_A map of Faerûn's whole Underdark._
The Underdark's environment varied vastly from the surface world, making adventuring through it a dangerous expedition. Just like when trekking through a desert, adventurers traversing the Underdark's passages needed to be well prepared.<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup>
The Underdark was mainly without any source of light save for the occasional luminous rocks or [fungi](https://forgottenrealms.fandom.com/wiki/Fungus "Fungus"). Large portions of it were also without food or water, making well-stocked food supplies a must-have when exploring uncharted terrain underground.<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup> <sup> [\[12\]](#cite_note-UD-p106-107-12)</sup>
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.<sup> [\[13\]](#cite_note-UD-p106-13)</sup>
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.<sup> [\[14\]](#cite_note-UD-p107-14)</sup>
[
](https://static.wikia.nocookie.net/forgottenrealms/images/6/66/Underdark_2650_2.jpg/revision/latest?cb=20200412000454)
_Fungi of the Underdark._
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.<sup> [\[15\]](#cite_note-UD-p107-108-15)</sup>
The Underdark was inhabited by many races, including [aboleths](https://forgottenrealms.fandom.com/wiki/Aboleth "Aboleth"), [beholders](https://forgottenrealms.fandom.com/wiki/Beholder "Beholder"), [cloakers](https://forgottenrealms.fandom.com/wiki/Cloaker "Cloaker"), [derro](https://forgottenrealms.fandom.com/wiki/Derro "Derro"), [drow](https://forgottenrealms.fandom.com/wiki/Drow "Drow"), [duergar](https://forgottenrealms.fandom.com/wiki/Duergar "Duergar"), [dwarves](https://forgottenrealms.fandom.com/wiki/Dwarves "Dwarves"), [illithids](https://forgottenrealms.fandom.com/wiki/Illithid "Illithid"), [kuo-toa](https://forgottenrealms.fandom.com/wiki/Kuo-toa "Kuo-toa"), [quaggoths](https://forgottenrealms.fandom.com/wiki/Quaggoth "Quaggoth"), [rock gnomes](https://forgottenrealms.fandom.com/wiki/Rock_gnome "Rock gnome"), and [svirfneblin](https://forgottenrealms.fandom.com/wiki/Svirfneblin "Svirfneblin").<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup>
Plant life and animal life could be as varied underground as on the surface, ranging from small insects to [hook horrors](https://forgottenrealms.fandom.com/wiki/Hook_horror "Hook horror") or [shadow dragons](https://forgottenrealms.fandom.com/wiki/Shadow_dragon "Shadow dragon"), which set up their realms deep down. Anything 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](https://forgottenrealms.fandom.com/wiki/Faerzress "Faerzress")_ for their energy.<sup> [\[16\]](#cite_note-UD-p108-16)</sup> The basis of the Underdark food chain were [magivores](https://forgottenrealms.fandom.com/wiki/Magivore "Magivore"): [coral](https://forgottenrealms.fandom.com/wiki/Coral "Coral")\-like organisms that likewise fed off _faerzress_.<sup> [\[17\]](#cite_note-FRCG-p218"-17)</sup>
Some dangerous flora of the Underdark were the exploding [bibberbangs](https://forgottenrealms.fandom.com/wiki/Bibberbang "Bibberbang").
Like many natural formations on the Material Plane, the Underdark had counterparts in the [Feywild](https://forgottenrealms.fandom.com/wiki/Feywild "Feywild") and the [Shadowfell](https://forgottenrealms.fandom.com/wiki/Shadowfell "Shadowfell"). In the Feywild, there existed the [Feydark](https://forgottenrealms.fandom.com/wiki/Feydark "Feydark" In the Shadowfell, there existed the [Shadowdark](https://forgottenrealms.fandom.com/wiki/Shadowdark "Shadowdark").
“
Absence of light results in darkness. So, what results from the absence of [Good](https://forgottenrealms.fandom.com/wiki/Good "Good")? The Underdark is a place with very little of either.
”
— Mordenkainen<sup> [\[5\]](#cite_note-MToF-pp189-5)</sup>
Contents
Geography\[(https://forgottenrealms.fandom.com/wiki/Underdark?veaction=edit§ion=1 "Edit section: Geography")\]
Domains\[(https://forgottenrealms.fandom.com/wiki/Underdark?veaction=edit§ion=2 "Edit section: Domains")\]
The Underdark was not one giant cavern under [Faerûn](https://forgottenrealms.fandom.com/wiki/Faer%C3%BBn "Faerûn"), but rather many huge networks of caverns and caves. As a result, it was not always possible to travel from one end of the Underdark to the other. The Underdark was divided into several domains that were similar to continents of the world above. While it was possible to travel from one place to another within a domain, separate domains tended to have very few passages linking them. The major domains of the Underdark were the [Buried Realms](https://forgottenrealms.fandom.com/wiki/Buried_Realms "Buried Realms"), the [Darklands](https://forgottenrealms.fandom.com/wiki/Darklands "Darklands"), the [Deep Wastes](https://forgottenrealms.fandom.com/wiki/Deep_Wastes "Deep Wastes"), the [Earthroot](https://forgottenrealms.fandom.com/wiki/Earthroot "Earthroot"), the [Glimmersea](https://forgottenrealms.fandom.com/wiki/Glimmersea "Glimmersea"), [Great Bhaerynden](https://forgottenrealms.fandom.com/wiki/Great_Bhaerynden "Great Bhaerynden"), the [Northdark](https://forgottenrealms.fandom.com/wiki/Northdark "Northdark"), and [Old Shanatar](https://forgottenrealms.fandom.com/wiki/Old_Shanatar "Old Shanatar").<sup> [\[7\]](#cite_note-UD-p122-126-7)</sup>
Topography\[(https://forgottenrealms.fandom.com/wiki/Underdark?veaction=edit§ion=3 "Edit section: Topography")\]
[
](https://static.wikia.nocookie.net/forgottenrealms/images/f/f2/Drizzt%27s_Underdark_Map.jpg/revision/latest?cb=20230815055616)
_A map of the Underdark beneath western Faerûn._
The Underdark's underground landscape varied from small subterranean fissures almost impossible for adventurers to crawl through to more conventional caves and caverns. But there were also wide expanses of deep water in which coral caves grew, blocks of ice that creatures hollowed out and dwelt inside, and cave-like spaces within masses of fungus or bone or else supported by bubbles of magical [force](https://forgottenrealms.fandom.com/wiki/Force "Force").<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup> <sup> [\[8\]](#cite_note-UD-p100-8)</sup>
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.<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup> <sup> [\[8\]](#cite_note-UD-p100-8)</sup>
Maztica\[(https://forgottenrealms.fandom.com/wiki/Underdark?veaction=edit§ion=4 "Edit section: Maztica")\]
The Underdark burrowed deep under the [Trackless Sea](https://forgottenrealms.fandom.com/wiki/Trackless_Sea "Trackless Sea"), stretching between the continents of [Maztica](https://forgottenrealms.fandom.com/wiki/Maztica "Maztica") and Faerûn. Ancient [dwarven](https://forgottenrealms.fandom.com/wiki/Dwarf "Dwarf") 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 the Maztican Underdark with their eastern kin.<sup> [\[9\]](#cite_note-IH-p61-9)</sup> In fact, the catastrophe was known as [Rockfire](https://forgottenrealms.fandom.com/wiki/Rockfire "Rockfire") and took place many dwarven generations before the "discovery" of Maztican continent by [Amn](https://forgottenrealms.fandom.com/wiki/Amn "Amn"). The calamity was caused by uncontrolled magics of the _[Darkfyre](https://forgottenrealms.fandom.com/wiki/Darkfyre "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](https://forgottenrealms.fandom.com/wiki/Faer%C3%BBn "Faerûn"), with passing centuries became [desert dwarves](https://forgottenrealms.fandom.com/wiki/Desert_dwarves "Desert dwarves") who lived in shallow caves close to the surface of the [House of Tezca](https://forgottenrealms.fandom.com/wiki/House_of_Tezca "House of Tezca") desert. 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–14<sup> th</sup> century DR.<sup> [\[10\]](#cite_note-IH-p269-10)</sup> The Underdark passages between the two continents were believed to be lost legends, gone, and forgotten by inhabitants of Faerûn.<sup> [\[9\]](#cite_note-IH-p61-9)</sup>
Laerakond\[(https://forgottenrealms.fandom.com/wiki/Underdark?veaction=edit§ion=5 "Edit section: Laerakond")\]
_Main article: [Abeiran Underdark](https://forgottenrealms.fandom.com/wiki/Abeiran_Underdark "Abeiran Underdark")_
When the [Spellplague](https://forgottenrealms.fandom.com/wiki/Spellplague "Spellplague") brought the continent of [Laerakond](https://forgottenrealms.fandom.com/wiki/Laerakond "Laerakond") to Toril, it also brought a part of the [Abeiran Underdark](https://forgottenrealms.fandom.com/wiki/Abeiran_Underdark "Abeiran Underdark") below it. It was different from the Underdark of Faerùn, but besides that it was inhabited by drow and mysterious monsters, little was known about this region.<sup> [\[11\]](#cite_note-Dra366-p52-11)</sup>
Environment\[(https://forgottenrealms.fandom.com/wiki/Underdark?veaction=edit§ion=6 "Edit section: Environment")\]
[
](https://static.wikia.nocookie.net/forgottenrealms/images/f/fe/Underdark_3e_map.jpg/revision/latest?cb=20240913122904)
_A map of Faerûn's whole Underdark._
The Underdark's environment varied vastly from the surface world, making adventuring through it a dangerous expedition. Just like when trekking through a desert, adventurers traversing the Underdark's passages needed to be well prepared.<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup>
The Underdark was mainly without any source of light save for the occasional luminous rocks or [fungi](https://forgottenrealms.fandom.com/wiki/Fungus "Fungus"). Large portions of it were also without food or water, making well-stocked food supplies a must-have when exploring uncharted terrain underground.<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup> <sup> [\[12\]](#cite_note-UD-p106-107-12)</sup>
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.<sup> [\[13\]](#cite_note-UD-p106-13)</sup>
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.<sup> [\[14\]](#cite_note-UD-p107-14)</sup>
Climate\[(https://forgottenrealms.fandom.com/wiki/Underdark?veaction=edit§ion=7 "Edit section: Climate")\]
[
](https://static.wikia.nocookie.net/forgottenrealms/images/6/66/Underdark_2650_2.jpg/revision/latest?cb=20200412000454)
_Fungi of the Underdark._
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.<sup> [\[15\]](#cite_note-UD-p107-108-15)</sup>
Inhabitants\[(https://forgottenrealms.fandom.com/wiki/Underdark?veaction=edit§ion=8 "Edit section: Inhabitants")\]
The Underdark was inhabited by many races, including [aboleths](https://forgottenrealms.fandom.com/wiki/Aboleth "Aboleth"), [beholders](https://forgottenrealms.fandom.com/wiki/Beholder "Beholder"), [cloakers](https://forgottenrealms.fandom.com/wiki/Cloaker "Cloaker"), [derro](https://forgottenrealms.fandom.com/wiki/Derro "Derro"), [drow](https://forgottenrealms.fandom.com/wiki/Drow "Drow"), [duergar](https://forgottenrealms.fandom.com/wiki/Duergar "Duergar"), [dwarves](https://forgottenrealms.fandom.com/wiki/Dwarves "Dwarves"), [illithids](https://forgottenrealms.fandom.com/wiki/Illithid "Illithid"), [kuo-toa](https://forgottenrealms.fandom.com/wiki/Kuo-toa "Kuo-toa"), [quaggoths](https://forgottenrealms.fandom.com/wiki/Quaggoth "Quaggoth"), [rock gnomes](https://forgottenrealms.fandom.com/wiki/Rock_gnome "Rock gnome"), and [svirfneblin](https://forgottenrealms.fandom.com/wiki/Svirfneblin "Svirfneblin").<sup> [\[3\]](#cite_note-FRCS3e-p210-3)</sup>
Ecology\[(https://forgottenrealms.fandom.com/wiki/Underdark?veaction=edit§ion=9 "Edit section: Ecology")\]
Plant life and animal life could be as varied underground as on the surface, ranging from small insects to [hook horrors](https://forgottenrealms.fandom.com/wiki/Hook_horror "Hook horror") or [shadow dragons](https://forgottenrealms.fandom.com/wiki/Shadow_dragon "Shadow dragon"), which set up their realms deep down. Anything 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](https://forgottenrealms.fandom.com/wiki/Faerzress "Faerzress")_ for their energy.<sup> [\[16\]](#cite_note-UD-p108-16)</sup> The basis of the Underdark food chain were [magivores](https://forgottenrealms.fandom.com/wiki/Magivore "Magivore"): [coral](https://forgottenrealms.fandom.com/wiki/Coral "Coral")\-like organisms that likewise fed off _faerzress_.<sup> [\[17\]](#cite_note-FRCG-p218"-17)</sup>
Some dangerous flora of the Underdark were the exploding [bibberbangs](https://forgottenrealms.fandom.com/wiki/Bibberbang "Bibberbang").
Characters in Location
Related Reports (Secondary)
Inhabiting Species
Related Materials