The surface world of Faerûn, the Forgotten Realms, is dotted with villages, towns, and cities, and all of these are signs of civilization. What few on the surface truly grasp, however, is that the Underdark, a world made up of winding passages and deep caverns below their feet, is populated with civilizations as well. While most know dwarves live under the mountains and others have heard stories of the evil dark elves, the drow, only the rarest surface dweller has traveled to their majestic cities and secret halls.

Aboleths: Aboleths are huge, loathsome amphibians that resemble bloated fish. These 20-foot, blue-green aberrations have four tentacles and a series of centrally located red eyes lined up one above another. Aboleths are both cruel and highly intelligent. They have puissant psionic powers capable of creating illusions and enslaving most any creature that crosses their paths (and sometimes transforming them into misbegotten piscine humanoid servitors called skum). Moreover, most are also powerful spellcasting clerics or sorcerers. The creatures lack a large city in the northern Realms, but they still exist in Skullport, the undercity found below Waterdeep, and they serve the nefarious aims of the secretive Kraken Society.

Beholders: Also known as "eye tyrants," beholders are a race of levitating, 6-foot wide orbs dominated by a central eye and a large, toothy maw, with ten smaller eyes on stalks sprouting from the top of the orb. The central eye of these monstrosities produces a cone of antimagic to hamper foes, while the ten smaller eyes shoot different offensive magical effects to deal with their foes. Some beholders punch out their own central eye to gain the ability to cast wizard spells. These shrewd creatures consider all other races to be lesser and subservient to their own greatness. Several of Skullport's most prominent crimelords are beholders. Beholder cities (known as "hives") are most prominent in central and southern Faerûn. Several offshoots of the beholder race exist, such as the death kiss, eyeball, and gouger, and each race has a differing number of eyestalks and supernatural powers.

Chitines: These creatures are the result of drow experiments gone awry. Chitines were once dwarves, and they were tortured and transformed into four-armed, bestial, spiderlike humanoids. These cast-offs escaped their masters, bred true, and formed their own primitive society in a region known as Yathchol, where they adopted the worship of their evil creators, that of the wicked Lolth, Queen of Spiders. Less civilized than her favored drow, Lolth has still gifted these faithful with her power, transforming her chitine priestesses, the choldrith, into giant, bloated, white spiders with humanoidlike heads and hands on their front legs.

Drow: Without question the most widely known and feared race of the Underdark, the drow or "dark elves" are the ebon-skinned, white-haired cousins of the goodly surface elves. They are as beautiful -- perhaps even more so than their kin -- and gifted with inherent magical powers and spell resistance. Cast down with their chief goddess, Lolth, centuries ago, these elves have adapted to their new environment and lost the ability to withstand the light of day. Most drow cities are dominated by the worship of their demonic goddess, who favors her female clergy and relegates males to lesser stations. The matriarchs of drow society often consort with fiends, giving birth to four-armed, bestial, half-drow known as draegloths. As powerful as the matriarchs of drow society are, the males are often themselves mighty warriors, wizards, and assassins. However, any drow that fails the Queen of Spiders runs the risk of being transformed into a drider, which is an insane drow with the lower body of a giant spider.

Most drow dream of conquering the surface world and subjugating other races to their evil whims. However, their own endless machinations and internecine wars prevent the dark elves from achieving their goal. In the North, dark elf cities include the long-fallen Chaulssin, Eryndlyn, the recently-fallen Ched Nasad, and Menzoberranzan, home to the exiled heroes Drizzt Do'Urden and Liriel Baenre. Drow are also found in numbers in the cities of Mantol-Derith, Skullport, and throughout the Underdark, though many of these smaller settlements lack the matriarchal theocrats of Lolth, and they have founded male-dominated societies dedicated to her wicked son Vhaeraun or redemption with her benevolent daughter Eilistraee.

Dwarves: Most subraces of dwarves live in the Realms Below. There they reside in well-organized, industrious cities and kingdoms, and craft amazing arms and machinery from the metal and stone bounties of the earth.

The most feared of the dwarven race are the degenerate and evil duergar or "gray dwarves," who have the magical ability to become invisible and increase their stature. These dwarves are a slim, gray-skinned people of about 4 feet in height. They are as mercantile and expansionistic as is practical. They will as easily trade with the drow, though they have no greater love for them, as they will war with them. Occasionally, a duergar will unwittingly breed with a devil and give birth to a half-fiend known as a durzagon. These creatures are somewhat taller than their duergar kin and empowered with dark powers, poison-secreting beards, claws, and fiendish resistances to many forms of attack. The duergar are sometimes joined by their chaotic, pale-skinned, and arcane cousins, the derro, who are rumored to be the result of magical cross-breeding between dwarves and humans. The city of Gracklstugh is the largest population of duergar in the North, though they are also fairly common in Mantol-Derith and Skullport, where they work as merchants and craftsmen. The derro are rumored to have a city of their own, named Tsenviilyq, which is below the High Moor to the south.

The largest subrace of dwarves in the North is the gruff, but kind, shield dwarves. These fair-skinned and sturdy folk are most commonly found in caverns relatively close to the surface world where they often interact with the humans that populate most of the civilized North. In fact, several great dwarven cities have joined with human and elven populations to form the new nation of the Silver Marches. Shield dwarves, however, are found throughout the Underdark, particularly in the Fardrimm region below the Silver Marches. In addition, the Stoneshaft Clan recently retook its clanhold in the Underdark north of Waterdeep. The shield dwarves are sometimes joined by their divinely blessed cousins the urdunnirs. These dwarves are known as the Children of Dumathoin after their divine patron. Their inborn magic allows for them to manipulate metals and stones as if they were clay and walk through the earth as if it were air.

Illithids: Illithids are mauve, rubbery-skinned humanoids, and each has a head that looks like a four-tentacled octopus with bloated white eyes. These hideous creatures, also known as "mind flayers," use their psionic and magical powers to enslave creatures and feast on their brains -- a prospect that strikes fear in even the hearts of the drow. Illithid cities are led by an elder brain, which is a free-floating mass made up of the brains of dead mind flayers. The elder brain also feeds off of the young mind flayer tadpoles that share its pool, culling the weak. Several illithid cities are found throughout the North, including Ch'Chitl, Gauntlgrym, and Llacerellyn. Mind flayers are also found working -- often as advisors, sages, and slavers -- in most other Underdark cities, including Menzoberranzan and Skullport.

Minotaurs: Not normally found in the Underdark in numbers, minotaurs are occasionally found as mercenaries, slaves, or even circus exhibits in the Realms Below. However, these powerful, bull-headed humanoids live in numbers in the region called the Labyrinth, where they prey on travelers and merchants passing through the extended cavern network. There, the minotaurs worship their demon-god Baphomet and are led by his minions and their planetouched descendants, the baphotaurs.

Svirfneblin: Svirfneblin, also known as "deep gnomes," are one of the few good-inclined races of the Underdark. These wiry, rock-colored folk are completely bald, and they stand just over 3 feet tall. Like most of the Underdark's races, the svirfneblin are highly magical and gifted with some natural powers of illusion and a certain amount of spell resistance. Despite their benevolent nature, the deep gnomes have become very isolated since they are surrounded by the evil races of the Realms Below. Until just a few years ago, the svirfneblin lived in the great city of Blingdenstone. Unfortunately, the drow of Menzoberranzan destroyed their great city, and the gnomes found themselves forced into hiding or closer to the surface, where they have allied with the Silver Marches.

Tanarukks: Bred from orc slaves and demons, tanarukks are powerful, stocky, planetouched humanoids gifted by their demonic heritage with fire and spell resistance and the power to control flames. They have coarse hair, gray-green or brown skin, and prominent lower tusks jutting from their bestial faces. These barbarians are led by two half-fiends, Kaanyr Vhok, the Sceptered One, and his consort, Aliisza. Originally found below the now-ruined Hellgate Keep, Vhok has encouraged his tanarukks to breed quickly into a large army, and he and his forces have taken the Underdark lands known as Ammarindar for their own. Given their rapid rate of reproduction and the expansionist desires of Vhok, the tanarukks pose a threat to much of the Underdark and perhaps even the surface world.

Lesser Races: Numerous other races of note live in the Underdark, though most of them are more common on the surface world, and they often end up serving as mercenaries and slaves in the Realms Below. These include most of the less civilized, warlike humanoid races such as bugbears, hobgoblins, goblins, orcs, ogres, trolls, and the reptilian kobolds, as well as the more primitive gibberlings and quaggoths.