In the Water Margin
Cao Zheng comes from a family of butchers in Kaifeng, so skilled at cutting and boning that he is called Demon Butcher. He once learned martial arts from Lin Chong. Sent to Shandong to trade with a rich man's money, he lost it all, married into a farming family and opened a tavern. There Yang Zhi, having lost the birthday gifts, eats without paying and fights him, until the two learn who the other is.
Cao Zheng suggests Yang Zhi take Two Dragon Mountain, but its chief Deng Long has shut the pass against Lu Zhishen as well. Cao Zheng devises a ruse: he ties up Lu Zhishen with a slipknot and brings him up as a captive, and once inside the monk breaks free and kills Deng Long. Cao Zheng later joins Liangshan with the Two Dragon band, is put in charge of slaughtering cattle, horses and pigs, and takes seat eighty-one beneath the Diji star.
