Historic Biography:
Zuo Ci was an elderly Taoist sorcerer, who strongly disliked Cao Cao for his brutal ambitions. He haunted Cao Cao multiple times, although in the beginning they were on more or less good terms. Zuo Ci made himself at home in front of Cao Cao and promised him eternal life and etc. through strange gifts, charms, and fruit. Their relationship soured when Cao Cao saw that Ci was scornful and hating toward him, and Cao became afraid of the great power he seemed to possess. Cao ordered him captured, and once Ci was prisoner he tortured him mercilessly.
However, Ci was never affected or injured, although he eventually died. Before he died, though, he haunted Cao Cao with an army of ghosts.