Jo San is the older son of Jo Shou and the older brother of Jo Yon. Information about Jo San is primarily provided through a story their father tells them about the past. In that account, Jo Shou recounts to both Jo San and Jo Yon the history of a girl named Houhou and how she came to live with the Jo family. The narrative details that when Jo Shou was a child, his own parents saved a quiet young girl named Houhou from attackers in the mountains of the Chinese countryside. Houhou had lost her memories and could only recall her name. She came to live with the family, where she trained rigorously to control her ki, and Jo Shou would spend time training and farming alongside her. The village later came under attack by bandits, who targeted Houhou, leading to a confrontation where Jo Shous father was threatened. While this story establishes Jo San as a member of the Jo family lineage, the events related concern the generation before him.

Physically, Jo San is recognized as an adult male with gray eyes and black hair worn at ear-length. He is often depicted wearing a suit and glasses.

No further reliable information regarding his specific personality, personal motivations, independent role in the story, key relationships beyond his immediate family, character development, or notable abilities is available for a comprehensive description.