Kame

Usagi's best friend since childhood, they are like sisters to one another. She is a beautiful and outstanding ninja, but had once been picked on for being a slow learner and Usagi would have to save her. She graduated second-to-last, in front of only Usagi, as she would constantly give into Usagi's demands to play. When she discovers that Usagi is Hanzo's bride elect, Kame is relieved that someone will care for Usagi when she cannot. While she loves Goemon, Kame becomes Ranmaru's lover in order to learn about the plans for the attack on Iga; she has no compunction whatsoever to seduce any man and kill him to protect her home and Usagi. Kame dies saving Usagi during the attack on Iga. Source: Wikipedia