Drow are dark elves, in most D&D settings they are among the greatest forces of evil with huge underground empires. They are normally hated by almost all other races.
In most campaigns drow have dark, black or blue-black skin and white hair.
Drow players are outcast for one reason or another, especially since you cannot start plying an evil character on Layonara. Some of the other characters will resent you if are a drow.