Kagemitsu Hazama is Mio Hazama's husband and Black Jack's father. He left his wife and son and escaped to Macau, China with his new wife but his actions are explained in the Black Jack 21 series. In chapter U-18 Knew of the manga, it is said that he lives in Hong Kong with his wife.
Kagemitsu is an intelligent and dedicated person, as is his son, Black Jack. He worries so much about his family that he was forced to stay in Macao, China with his new wife, fearing that the organization of the Noir Project would persecute them.
Kagemitsu works as a hospital staff in a New York hospital. There he met Mio, who also works in the same hospital as a nurse. He left his job and decided to join the Nior Project, a secret project in which the world's celebrities also participated. One day, she reunited with Mio once again after returning to save her friend's wife, giving her a mechanical heart that she created in the project. In Central Park, she confesses her love to Mio and went to Japan to get married. There, Black Jack was born. After refusing to resume Project Noir, the organization that threatens to place a bomb on the beach, where Black Jack and Mio were. The bomb exploded, almost killing them, and Kagemitsu was forced to flee to Macao, China with his new wife, fearing for the safety of his family.
In China, Kagemitsu started a new family with his new wife. He was reunited once again with his son, Black Jack and asked him to operate on his wife's face. During a father and son conversation, he lied by saying that he doesn't love Mio for the sake of protecting his family for 21 years. Later, he fell into a coma for a few days and passed away soon after.