Kray refers to the Kray twins, Ronald and Reginald Kray, who were notorious British gangsters in the 1950s and 1960s. They led a criminal organization in East London, engaging in various illegal activities, including extortion, robbery, and murder. The twins were known for their violent behavior and their connections to the London underworld. The Kray twins gained notoriety not only for their criminal exploits but also for their public personas, often mingling with celebrities and high-profile figures. Their lives were marked by a blend of crime and glamour, which has been depicted in various films and books, contributing to their lasting legacy in popular culture.