Criminal Orginizations of the Planes
Dark Eldar Warbands: Groups of pirates that put the worst reavers to shame.
Scarlett Brotherhood: A loose brotherhood of assassins, alcemists, thieves, and pirates that deals in all manner of vices. They will work for anyone as long as they have the coin.
Spider Clan: A gathering of assassins, thieves, ninjas, and spellcasters; that have banded together around seventy five years ago. Believed to have around 125 members, but due to their secretive ways there is no way to be totally sure.