Natsume is a young woman who is an itinerant martial artist along with her younger sister, Kurumi. For years the two wandered Japan in search of their long-lost father, Soun Tendo. They briefly usurped Akane Tendo and Ranma Saotomeâ€™s claim to inherit the Tendo Dojo and carry on Anything Goes Martial Arts after challenging and defeating them, but conceded their claim following a rematch.
Both sisters are the only characters to appear in the OVAs who did not originally appear in the manga.
(Source: Ranma Wikia)