The vast majority of Dark Elves may be found in the Dark Elves Village, exiled there for the crimes of their ancestors.
Dark elves are descended from elves, and share most of the same traits. One visible difference is skin color; the dark elves are blue which other races view as a sign of corruption..
In the distant past their ancestors consorted with demons, tainting their blood. One side effect of this is that their very presence can corrupt, and eventually kill the forest.
As time passed, this taint has lessened to where they can move about the woods once more. However, this corruption can be reestablished by further congress with demonkind.