Gang leaders for now don't do much in the game. One thing gang leaders could do is to run illegal gambling operations that the player can invest in or participate in, in some form or another. The player can bet on tournaments or wars through gang leaders. The player can earn money from gamblers that deal with gang leaders that are in partnership with the player. Gambling could lead to quest like collecting money from characters that love to gamble. Nobles and notables could be degenerate gamblers or gang leaders maybe be angry that they have to pay an important character their winnings. Players with high roguery could have special advantages for this aspect of the game.
There could be illegal lotteries in the game too.
There could be illegal lotteries in the game too.