|Family:||Hotaru Tomoe (daughter), Professor Souichi Tomoe (husband)|
|First Anime Appearance:||Sunny Skies After a Storm! A Friendship Dedicated to Hotaru (flashback only)|
|First Manga Appearance:||Act 29 Mugen 6 - Three Senshi (flashback only)|
|First PGSM Appearance:||N/A|
|English Name:||Hotaru's mother|
Keiko Tomoe was the wife of Professor Souichi Tomoe and the mother of Hotaru Tomoe. She appeared in both the manga and anime, but in both cases she only appeared in photographs or brief flashback sequences, as she died before the start of the series. Her face was never shown in detail in the anime.
In the manga, Keiko was killed in a fire that broke out when lightning struck her husband's laboratory while he was doing research. The same fire also gravely injured her daughter, who was eight years old at the time. Professor Tomoe claimed that during her life Keiko wore an amulet made from Taioron Crystal, the power source for the Death Busters, which he would later give to Hotaru to soothe her pains. While Keiko herself only ever appeared in flashbacks, Hotaru still seemed to hold her in high regard, and possibly objected to Kaolinite trying to pursue her father because of that.
In the anime, Keiko's backstory was not elaborated on. However, she was shown with her face covered in shadows in episode 116 when Hotaru briefly recalled her happy memories.