| Mayumi Osaka |
|Residency:||Azabu-Juban, Minato-ku; Tokyo, Japan|
|Manga:||Act 1 Usagi - Sailor Moon|
She has light short wavy brown hair and wears fancy jewelry.
Mayumi Osaka runs a jewelry shop in Tokyo. When the Dark Kingdom began making its move to locate the Silver Crystal as well as collect energy, a youma locked Mayumi, tied up, in the basement of her building and took her form and identity in order to search for the Silver Crystal in the store and sell jewelry which would steal the wearer's energy. She and her daughter were saved by the newly-awakened Sailor Moon.