BB (ビィビィ, Byibyi?) is the name of the Sakura Matou-model Advanced AI originary to the Moon Cell. However, with time, multiple alternate versions and other characters sharing the same designation have been introduced:
- CCC Incident:
- BB: The original BB appearing in the World of Fate/EX. She has a brief appearance in the World of Fate/Grand Order during the SE.RA.PH Subcategory Singularity under the designation BB/GO.
- Sakura Five: The five Alter Egos created from BB.
- World of Fate/Grand Order:
- BB, also called Moon BB: A digital copy of the original BB summoned by the Moon Cell during the SE.RA.PH Subcategory Singularity to stop Beast III/R. She operates as the main BB in Chaldea.
- Summer BB: The version of Moon BB appearing in the first Servant Summer Festival. She has two alternate forms: BB Pele and BBhotep.
- BB Cosmos: The version of Moon BB appearing in Archetype Inception.
- Moon Dubai:
- BB Dubai, originally called Last Slot: A second generation AI native to the Moon Dubai Apra World. She was modeled after the original BB after being modified to better suit the management of Moon Dubai.
- Golden BB: A version of BB Dubai that absorbed BB Cosmos' Saint Graph.