Yuen is nicknamed "Tequila" because he is a heavy drinker. His actual first name is unknown.
His first appearence was in the John Woo film "Hard Boiled". Stranglehold is the sequel to Hard Boiled, with Chow Yun Fat reprising his role as Inspector Tequila. He drinks tequilas at the jazz bar which he plays with his band. The bartender, played by John Woo himself, is used to having Tequila around. Tequila likes to use weapons akimbo-style, and can use any part of the environment as cover or a means of transportation. His ability to adapt to the situations has kept him alive through many encounters.