Hong Kong has a varied cast of ancient deities. But there is one god so popular that both police and gangsters worship him: Duke Guan, also known as Emperor Guan. He is not only a mythical character but also based on a historical figure, named Guan Yu.Duke Guan features prominently in Hong Kong popular culture, from the famous Young and Dangerous film series to TV dramas. Shrines to Duke Guan are commonly found in restaurants, shops, police stations and even thieves’ lairs.There are also…