|Family and Relations||Juzo Kabuto (Employer)|
|Voice Actor||Rihoko Yoshida|
|First Appearance||Mazinger Z episode 1|
Rumi was a young woman with short brown hair and brown eyes. In her only appearance she wore a pink long-sleeved shirt, a purple skirt, and a white apron.
Rumi was hired by Juzo Kabuto to look after his house and his grandchildren as he was busy with a secret project. She got along well with Shiro but grew concerned about Koji and his reckless attitude. When Dr. Hell sent Baron Ashura to go and kill Juzo Kabuto he/she first went round to the Kabuto household, he/she then forces Harumi to tell him Juzo's whereabouts before killing her in cold blood and leaving. Rumi was found later by Koji and Shiro; Shiro cried over her body as Koji went to check on their grandfather. She is never mentioned again afterwards.