|Stealthy and resourceful, assassins alone have the ability to stab an opponent in the back. Caution must be used, however--else this skill could come back to, well, stab yourself in the back. Another perk of being an assassin, besides all the cool black clothes, is the ability to collect bounties. Check out the Assassin's Guild for more info, on Death Row, opposite the graveyard.
The weapon of choice for an assassin is the dagger, and he hides his possessions well, so if you want to join their ranks, be sure to look in every nook and cranny.