|Lives:||A well at T·A Academy for Girls|
|First Anime Appearance:||N/A|
|First Manga Appearance:||Juken Sensou Hen 3 - Rei to Minako no Joshikou Batoru|
|First PGSM Appearance:||N/A|
|English Name:||Barbara S. (Mixx manga), Ghost Cistern (Kodansha manga)|
Ghost Cistern was a genius loci who appeared in the third Exam Battle side story. She had been sealed for 300 years in a well at T·A Academy for Girls before Minako opened it and released her. Ghost Cistern then possessed Rei's body and ran amok before Minako transformed into Sailor Venus and destroyed her.