Brook

Kumi Mashiba

間柴 久美
Kumi is Ryo Mashiba's sweet-natured, but hard-working and willful younger sister, and as such understands him better than anyone else. She will do almost anything to support her brother and make him happy, including going to his matches even though she doesn't like to see him get hurt. Ippo becomes infatuated with her early on. (Source: Wikipedia)