As told in drow histories, in ancient times a multi-planar goddess by the name of Lloth cast her eyes upon Aabahran and saw upon it a race of supreme intelligence and power. These were, of course, the ancient elves. But the elves were weak, lacking in spine and fettered by false laws and morality. Lloth revealed her divinity to a particularly powerful and ambitious elven mage named Xymerr, opening her eyes to the lies and falseness of elven ideals. Xymerr became the first high priestess of the spider queen, and set about finding other like-minded individuals. With the help of the goddess, Xymerr led a great exodus of the most intelligent, the most cunning, and the most ambitious of the ancient elves to the Underdark. Blessing them and marking them as her own, Lloth gave them a new name and a new appearance; 'drow' she named them, and a pitch-black skin she gave them, to let them fit in better with their new home. To the females alone did she grant her divine gifts, teaching that it was natural for females to rule and males to obey, in direct contrast to ancient elven notions of equality between the sexes.
Xymerr and her priestesses founded a new city in the Underdark, a terrible and splendid one, using a combination of divine power, wizardly might, and slave labor. This city they named 'Xymerria', in honor of Xymerr, who had led them here. The most powerful of the drow priestesses each enslaved armies of stone-cunning dwarves to build them mighty Houses from which they would rule. Xymerr's house, House Do'Rekdin, was set above all other houses, and Xymerr herself became the first Matron Mother of House Do'Rekdin and as close to an absolute ruler as the city would see. In a few short centuries, the drow became the most powerful, pre-eminent force in the Underdark, obliterating or enslaving nearly every other race, save for the duergar, whom they forced into a reluctant partnership, and the illithid, whom even they feared.
Seeing how well her new children had done, one more gift Lloth did bless the drow with. Iron is inimical to elves; it's very touch burns them. Lloth changed the biological and magical nature of her dark children so that, unlike the surface elves, they would no longer need to be wary of this most base of metals. Their new bane, silver, was too rare as well as too soft to pose a grave danger. The only reason that the drow did not overrun the surface in the early days when they were still united under the rule of Matron Xymerr was an unlikely partnership between the elves and the dwarves. The elves were wary of the growing power of the drow, and the dwarves held a deep hatred for Xymerr's drow for their enslaving of so many dwarves to build Xymerria. One clan in particular, Clan Mith, suffered tremendous losses from drow raids due to their exceptional brilliance and abilities, which were high in demand. For the first and only time, elves allowed dwarves from that clan, Clan Mith, to experiment upon them as well as the few captured drow prisoners they had. After countless sacrifices, Clan Mith managed to invent a new metal alloy that was lightweight, strong, and as inimical to drow as iron was to elves. They named this metal 'Mithril', roughly meaning 'Vengeance of Mith'; in time, 'mithril' became the name of both the alloy and its principle component. As soon as the drow learned of this development, they led a huge strike force that razed the halls of Clan Mith to the ground and enslaved or slew every dwarf, but too late. The metallurgical skills for making mithril had already been taught to every other dwarven clan. Matron Xymerr achieved her vengeance on Clan Mith, but her dreams of conquering the surface world, adding it to the drow fold, died. Shortly after, she died as well, murdered by her eldest daughter, who became the new Matron Mother of House Do'Rekdin.
But with the passage of time, the surface elves have lost much of their influence as other races, such as humans, became the dominant race on the surface. While in the deep, dark depths of the Underdark, the dark elves, the drow, reign supreme, as they have since the founding of Xymerria. And as any drow will tell you, is this not proof that Lloth and Matron Xymerr were right, and won in the end?
Lloth is a jealous goddess. With the passage of eons, her attention has been increasingly diverted from Aabahran to her many other flocks on other planes, but any drow who turns away from her can expect to have trouble for the rest of his or her life, often at the most untimely of moments. On occasion, she may allow drow who depart the Underdark to worship other gods in addition to her, but she never forgets one who wholly forsakes her.
Drow must stay evil to cast any spells they might know. Those who turn to good are frowned upon.
Very few drow are misshapen in any way, either in limb or in features. Drow, being the cruel, arrogant race that they are, disdain any weaknesses, and children who are born crippled or even slightly ugly are tossed to their beasts for food. Over time, this has produced a race of exceptional beauty, even by elven standards.
The highest ranking drow are the Matron Mothers of the Great Houses, followed by Matrons of the lesser Houses, high priestesses, and normal priestesses. Male drow are considered inferior to female drow, and a single word from a priestess can condemn most male drow to death. This is not the case in every situation, of course, and male drow of particular ability and ambition sometimes can rise to positions of great powerbut always are inferior to the Matron Mothers. Obedience to females is instilled in every male drow as a child with punishment and pain. Male wizards are watched with particular suspicion and care, as they possess great power that does not stem from obedience to Lloth or the priestesses. Regardless of their personal piety, almost all male wizards pay at least lip service to the spider queen, for fear of the wrath of her and her servants.
The assassination of superiors is not only accepted, it is considered the most efficient way for a drow to distinguish and advance oneself. Thus, Matron Mothers are commonly murdered by their daughters if they grow old and weak, or if they lose Lloth's favor. Weaponmasters are murdered by their star pupils, and archmages are poisoned by their prized apprentices. Deceit and trickery are second nature to them. Drow always look for angles and means by which they can advantage themselves and disadvantage their enemies. This has cultivated extreme paranoia amongst the drow.
Drow, especially those who are nobles of a House, rarely leave the Underdark for extended periods of time; those who do so are generally outcasts, exiles, or have been sent away on special missions. The spider queen and the Matron Mothers guard their flock with a jealous eye.
Drow possess all the arrogance of surface elves, and then some. They hold a universal, casual contempt for all surface races. Although they may be superficially polite, they are more likely to elaborately insult in such a way where the target of ridicule isn't even aware that they have been mocked. Generally speaking, the only use they have for surface races is that of slaves; they particularly prefer giants for this task, due to their brute strength and their slow minds. The many raiding parties they have led to acquire giant slaves have sown the seeds of serious enmity between the two races, although it pales in comparison to the shared hatred between drow and surface elves.
Out of all the races of the world, the only race which they respect and perhaps even fear is that of the illithid, a subterranean race of psionicists which are more intelligent and arguably more evil than even the drow. As the illithid are a reclusive people which rarely venture forth from their Hive save to acquire slaves, they have never been interested in challenging drow supremacy of the Underdark, despite their own formidable prowess. Relationships between the two races have thus generally been cordial. Nonetheless, the illithids' powerful psionic abilities, casual cruelty and supreme intelligence are more than enough to make even the drow wary in their dealings with this particular race.