Cao was born in S.1179.
Publicly seen as the president of the Heiyue Trading, Ltd. in Crossbell, Cao is actually a manager within the Heiyue syndicate. He came to Crossbell to break Revache's foothold and take over the underside of Crossbell. To accomplish his goals, he contracted the legendary Calvardian assassin Yin.
When he first met the Special Support Section, he surprised them by correctly telling them their names, ensuring he already has his intelligence network in place. In August S.1204, he was contracted by Samuel Rocksmith to protect him during the West Zemuria Trade Conference.
During the Red Constellation attack on Crossbell City, the Heiyue branch at the Harbor District was burnt down to the ground. Cao concluded it would be best to team up with the Special Support Section and work toward Crossbell's liberation. After the confusion in the city settled, Cao re-opened the branch of Heiyue, which flourished with no rivals in Crossbell's illegal circuits.
Apart from his intelligence, Cao is also proficient in self-defense.