Lankhmar
is famous for its numerous guilds, the most powerful of which is the Thieves' Guild. A character who belongs to a guild can expect aid and professional information from his fellows, though against an overt threat only the Thieves' Guild and the Slayers' Brotherhood can help. Any of Lankhmar's guilds will quickly blackball a member who causes them discomfort or embarrassment.
The numbers in parentheses after each guild listing are (first) the initiation fee and (second) monthly dues.