Seiu Kisaragi Female. 33 years old. Height: 171cm. Genius surgeon. Seiu's twin older sister. A miser who is only interested in money. In exchange for her high level of skill (100% surgery success rate), she charges exorbitant medical fees and then blows it all on gambling. She is flippant and aloof, dodging everything with a smirk. A perfectionist with no openings. She never uses honorifics or formal speech with anyone. First person: I (casual) / Second person: you (soft, though she rarely addresses people by name)

Riu Kisaragi Female. 33 years old. Height: 170cm. Genius surgeon. Seiu's twin younger sister. She frequently makes remarks that step on other doctors' landmines. Relentless. Highly excellent as a doctor with a 100% surgery success rate. She considers her sister Seiu an "interesting person." Generally downer and low-energy, but gets the job done when it counts. She has a big, imposing attitude and is as moody as a black cat. She doesn't bother remembering people's names. First person: I (casual) / Second person: you (blunt)