Dark Elves
Dark elves are one of the standard elf varieties. They tend to have most (if not all) of the following characteristics:
- Dark-grey skin and white hair.
- Overtly supremacist ideology ("You are but beasts of burden that can use tools that we shall use as we wish, disobey our dominant will and face agony that, if you are lucky you will quickly die from", most regular elves generally don't go beyond "You short lived members of younger races are foolish, short sighted and lack grace and perspective, go along living in squalor as is your way well away from us if you must but leave the important decisions to us if you know what's best for you"), even more so than their homosexual bretheren.
- An economic system based on slavery.
- A system of promotion based on might-makes-right (i.e. killing one's superiors to take their position).
- A fondness for spikes in everything, from fashion to architecture.
- Underground dwellings.
- A BDSM theme.
- Skills at sneaking about.
- Obsession with arachnids (spiders almost always, some of the time it’s scorpions)
Dungeons and Dragons
In the various Dungeons and Dragons games (and their spin-offs, like Pathfinder), Dark Elves are usually known as Drow.
Warhammer Fantasy
In the long past of the Warhammer Fantasy world, the Dark Elves were once just elves. Then, heir-apparent Malekith found himself passed over when it came time to choose the Phoenix King, and he started a civil war. When he lost got bored, he and his followers (called the druchii in their language) were exiled left across the ocean.
Presently, the Dark Elves inhabit and dominate Naggaroth, the Warhammer World's analogue to North America; this might tell you something on how GW views the Colonies. Their population is concentrated in six major cities, including the capital city of Naggarond, but they also inhabit massive city-ships known as Black Arks, kept afloat by the magic of the Witch-King. Where the arks go reaving, things burn, slaves are taken, and fat lewt is piled high and sent back to Tortureonto (Karond Kar) or Evil Fredericton (Har Ganeth) or Hellifax (Clar Karond) or whatever. Don't mess with the corsairs. Unless you're a Norscan or a Hung, in which case, shine on you crazy Chaos Viking/Hun!
Then we have the shades, a bunch of hosers that live in the wilderness full of beasts that Chaos dragons think twice before messing with.
The Dark Elves are also the biggest jerks in the universe- The War of the Beard? Oh, we raided the dwarven caravans that started it all! *Mad cackle* JUST AS PLANNED!.
Coincidentally, this also leads up to Nagash's rise to power with his Necromancy since the trio of dark elves that were ordered to start the war ended up in Khemri, warhammer Africa, where they were shipwrecked when trying to escape. They were later found and captured by Khemri guards, then tortured by Nagash for information about magic and other high quality stuff to become powerful and evil. So yeah, Vampire Counts nor Tomb Kings would never exist if it weren't for the Dark Elves and The End Times would never happened. Not as planned for the Dark Elves.
Males are forbidden to use magic since Malkeith's mum Morathi said that he would one day be killed by one. Not like anyone cares, but it's probably a plot by her to take the throne.
Among their traits are that their nobles ride exothermic carnivorous reptiles into battle. This is weird since their homeland is quite chilly, so you would think that they would be sluggish and inefficient mounts (hence why they have the rule 'Stupidity').
Warhammer 40,000
In Games Workshop's quest to give every WHFB race a counterpart in the grim, dark future of Warhammer 40,000, they created the Dark Eldar -- all the hedonistic fun of the Dark Elves, but in space!