Eddie Kessler (Anthony Laciura) is Nucky’s German man servant. In the show, his character adds a tiny amount of comic relief with his bumbling actions. v is based on Louis Kessel, a retired cab driver who was Nucky’s butler while he lived in the Ritz-Carlton. He was Nucky’s driver and bodyguard, and was later arrested for prostitution. I assume he wasn’t the one turning tricks.
Al Capone (Stephen Graham) is shown in a manner audiences are not familiar with on screen; a young family man just starting out in a life of crime. His character is based directly on the real-life crime boss who ruled Chicago and was one of the biggest bootleggers during prohibition. I love DeNiro as Capone in The Untouchables, but Graham is one hell of an actor and is great in the show.
Arnold Rothstein (Michael Stuhlbarg) is one of the dealers players in Nucky’s empire. His goal is to move liquor from Atlantic City to New York. Like Capone, his character is relatively accurate, and is based on the real-life gambler and businessman who rose to the top of the Jewish mafia. In the show and in real-life, Rothstein was known for wearing bow ties, and was reputed to have fixed the 1919 World Series.