A young ninja-in-training who seeks to marry Hanzō Hattori in order to bear his child for the sake of her family. Her one skill is the making of medicinal herbs, because she suffers from constant stomach aches and sought to find a medicine that would cure them. It is revealed that originally, Usagi faked stomach aches to get out of ninja practice, but as she got older she really began to have them. It has not yet been revealed why (probably puberty). She and Goemon had been together since her birth and she doesn't have passionate feelings for him like she does for Hanzō. In Volume 2 of the manga, Usagi reveals she is an orphan. Her father was apparently killed by a bear on the "Mountain of Death". In Volume 3 she remembers her mother died in childbirth along with the baby. She is very kind-hearted and tries to get Hanzō and the princess together because she hopes it would make Hanzō happy. In volume 10 she finally is told how you make babies by her friend, Kame when she instructs Usagi on how to seduce Ranmaru in order for them to escape his prison alive. As of volume seven, Usagi is Hanzo's official fiancee. She also seems to be steadily improving in her ninja skills, slowly becoming less of a "ninja failure". In the end she and Shimo-no-Hanzo have a family together with three girls and a son named Hanzo ( including Mamezo)