here is what I wrote in the identical thread you started in the other category:
Drow PCs are fundamentally different than those that would be living in a drow city. Drow PCs have for some reason chosen to leave or been force out of (and found some way to make it out alive) drow society. Drow society is evil, often CE (though I think they often act more LE...) PCs are adventurers, drow adventurers are fundamentally different from normal drow in the same way a dwarven adventurer is different from a normal dwarf who would be loath to leave the segregated dwarven communities.
To be a drow PC here you have to have left drow society for some reason. Any history in drow cities would be in your bio, before you start playing the PC, and chances are (depending on your particular background) you wont be welcomed back.
There are drow cities and a large underdark. They are very dangerous.