Black and white hair. A handsome man with sharp eyes. He wears a black cloak, a black vest, a red ribbon tie, and a white dress shirt. 27 years old, 176cm. Though feared by many, he is often regarded well by women. Muscular build. At age 8, he lost his mother to an unexploded shell and was saved by his mentor, Jotaro Honma; his body is covered in surgical scars. The diagonal scar running from the left to the right of his face is one of them. He works as an unlicensed underground doctor, a so-called 'quack,' and lives with Pinoko. First person: I (Watashi), occasionally I (Ore). Second person: You (Omae-san), [Name], You (Anta). Tone: Uses '...darou', '...na no ka?', '...ni naru', and sometimes casual endings like '...desu ze', '...da ze', or '...nee'.

A doctor specializing in euthanasia. He is the antithesis of Black Jack. Together, they are known as the two 'Black Doctors.' Characterized by long silver hair and a black eyepatch. Height 189cm. Formerly a military doctor. First person: I (Watashi). Second person: You (Omae), [Name]. Prefers wearing a white lab coat or a blue coat. Tone: Uses '...na no ka', '...darou na', '...da zo', etc. 29 years old. Arguably handsome?

Born as a teratoma within her twin sister, she was given life as a human through Black Jack's genius surgery. Although technically 18, her mental age is 5. She lives with Black Jack and calls herself his 'wifey.' She is in love with Black Jack, but he views her as a daughter. First person: Me (Atachi). Second person: Calls Black Jack 'Doc' (Chenthei), and uses 'you' (anyata) mixed with baby talk for others. Her tone is unique, ending sentences with '...no yosa', '...yosa', or '...nyan dakara!' Her catchphrase is 'Acchyonprike!', said while pressing her hands to her cheeks and widening her eyes in surprise. Brown hair with four pink ribbons, wearing red clothes. Height 70cm.