Frank Costello & Roy DeMeo | Mafia Crime Bosses Who Ruled the Underworld: br Discover the dark world of organized crime through the lives of two notorious Mafia figures — Frank Costello and Roy DeMeo. Costello, known as “The Prime Minister of the Underworld,” rose to power as a political mastermind who controlled New York’s underworld without firing a gun. In contrast, Roy DeMeo built his reputation as a ruthless enforcer who turned murder into a profitable business. This video explores their rise, power, and legacy inside the Mafia. Watch how two very different men shaped the history of organized crime in America’s most feared underworld.