The Drow are an offshoot of the elven race. Some, many of them elves, theorize that they were corrupted by an outside power. Others claim that they are simply elves who have embraced the darkness voluntarily. Either way, this powerful and ruthless society wields arcane powers both powerful and subtle, and are not to be underestimated.
Drow society is matriarchal, with woman holding most positions of power. The most powerful woman are clerics and priestesses of Lloth, the spider goddess of their race; such women rule over their cities and factions with divinely inspired fear and coercion. Male Drow can only hope to achieve power through military service or by exceptional mastery of the arcane arts, something difficult to do when one is part of an entire race of spellcasters. Those in power spend much of their time fighting one another for greater wealth or influence. This competitive infighting is constant, and permeates the every level of their culture, from the lowest peasant to the highest cleric of Lloth.
Taken from Wikipedia:
In ages past, the elves were torn by discord and warfare, driving out from their surface lands their selfish and cruel members, who sought safety in the underworld. These creatures, later known as the “dark elvenfolk” or drow, grew strong in the arcane arts over the centuries and content with their gloomy [land] beneath the earth, though they still bear enmity towards and seek revenge against their distant kin, the elves and faeries who drove them down. They are […] chaotic evil in alignment, and highly intelligent.
Black-skinned and pale haired in appearance, around 5-feet tall and slight of build with somewhat sharp features, with large eyes and large pointed ears. Their equipment (magical boots and cloaks, and fine mesh armor similar to chainmail) is black in color and described as being empowered by exposure to the strange radiations of the Drow homeland, losing this power and eventually falling apart when exposed to direct sunlight and kept from the radiation for too long.
Females are inherently more powerful than males, and only females may be clerics or fighter/clerics; male drow are commonly fighters, magic-users, or both classes at once. Drow move silently and with a graceful quickness, even when wearing their armor, and blend into shadows with ease. They carry long daggers and short swords of an adamantite alloy and small one-handed crossbows which shoot darts carrying a poison that causes unconsciousness.
Drow are difficult to surprise as they are able to see very well in the dark, have an intuitive sense about their underground world similar to that of dwarves, and can detect hidden or secret doors as easily as other elves do. Drow are highly resistant to magic, while all drow have the ability to use some inherent magical abilities even if they are not strictly spellcasters. There are rumors of vast caverns housing whole cities of drow which exist somewhere deep beneath the earth […]. They are able to communicate using a silent language composed of hand movements, and when coupled with facial and body expression, movement, and posture, this form of communication is the equal of any spoken language.