Haruka Takagi

Fujimaru's younger sister by two years. She suffers from kidney failure, requiring dialysis about every three days. Haruka seems to have a slight crush on Otoya. In the second season, she is shown to be much healthier, due to having been given a home dialysis machine from Otoya and his grandfather, allowing her to receive the treatment while she sleeps. She is often kept in the dark about events concerning Fujimaru and her father, for fear of the emotional stress impacting her health. (Source: Wikipedia)