Charles Dean O'Banion was an American mobster who was the main rival of Johnny Torrio and Al Capone during the brutal Chicago bootlegging wars of the 1920s. The newspapers of his day made him better known as Dion O'Banion, although he never went by that first name. He led the North Side Gang until 1924, when he was shot and killed, reportedly by Frankie Yale, John Scalise and Albert Anselmi.

Vincent Drucci, also known as "The Schemer", was an American mobster during Chicago's Prohibition era who was a member of the North Side Gang, Al Capone's best known rivals. A friend of Dean O'Banion, Drucci succeeded him by becoming co-leader. He is the only American organized crime boss to have been killed by a policeman.