Yagyuu Kyuubei (柳生 九兵衛, Yagyuu Kyuubei) is the successor to the Yagyuu family name, the daughter of Yagyuu Koshinori and granddaughter of Yagyuu Binbokusai. She was brought up as a male, following the code of the Yagyuu clan, but in later years decided to follow neither femininity or masculinity, but live as only "Yagyuu Kyuubei". She is the main antagonist of the Yagyuu Arc.