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 Saotome’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)
Kurumi is a young woman who is an itinerant martial artist along with her older sister, Natsume. For years the two wandered Japan in search of their long-lost father, Soun Tendo. They briefly usurped Akane Tendo and Ranma Saotome’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)
Ikuno Komaki is Manaka's little sister who has a chronic illness that keeps her in the hospital. Prior to episode two of the OVA, her health improved and she was released, thus she was invited to the beach along with her sister. Ikuno is very supportive of her sister and she tries her best to support Manaka in her affection towards Takaki.
Bohemian Girl who appeared in episode 4.5 (Special).
She was left for dead after the brutal murder of all members of her family, Henrietta is the newest addition to the Agency. She was assaulted repeatedly next to the dead bodies all night, which had inflicted psychological trauma to her, making her suicidal. Her struggle is the most developed of all the girls as she adjusts to her new life. Henrietta's favorite activity is to spend time with her handler, Jose`. Whenever Jose seems to turn his attention to other women (including the other cyborgs of the SWA), Henrietta becomes slightly jealous. This is due to Henrietta's strong romantic feelings for him, as a result of her faint conditioning and the care he gives her.