His real name was Cao Yi and he is said to have lived during the Song dynasty (960-1279 C.E.). As one of the Eight Immortals (Bāxiān 八仙), Cao Yi is called Cao Guojiu (曹國舅), which means ‘Imperial Brother-in-Law Cao’. This designation that refers to his sister having been the Empress Dowager Cao.
A quiet, unassuming man who liked to keep a low profile, Cao Guoji had, unfortunately, a younger brother (Cao Jingzhi 曹景植) who took advantage of his royal connections. This younger brother was a source of shame and frustration to Cao Guoji who tried to advise him to show better judgement and more restraint. Finally, having had no effect on Cao Jingzhi’s conscience, Cao Guoji retired to a cave to become a hermit.
Cao Guoji spent several years in his cave, meditating, contemplating nature and purifying his body. Eventually, he was approached by the immortals Lu Dongbin (呂洞賓) and Zhongli Quan who wished to test Cao Guoji’s progress as an ascetic.
It is said that the two elder immortals questioned Cao Guoji and, satisfied by his answers, taught him the secrets of the Dao, including its philosophy and magical arts. After several more years of study and practice, Cao Guoji became an immortal himself.
This immortal is the patron deity of actors and the performing arts. He is often depicted dressed in official robes and holding a jade tablet or castanets.