Celica is Konoe's younger sister, Jubei's sister-in-law, and Kokonoe's aunt. When she was a child, Celica's mother died due to an unknown sickness and her father was always holed up in his lab. She briefly traveled with Bloodedge during the Dark War, whilst trying to find information about her father, Shūichirō Ayatsuki. After the Dark War, she watched over the Black Beast's remains and built a church, waiting for a chance to reunite with Bloodedge. She later was the foster parent of Ragna, Jin and Saya, the three of them having been entrusted to her by Jubei. She was killed by Yūki Terumi in 2192. However, in BlazBlue: Phase Shift 4, Celica touched the Old Gate in Magister's City: Ishana; this made her enter the Boundary temporarily, setting the scene for her 'revival' many years later.

She was also the previous owner of the Nox Nyctores, Deus Machina: Nirvana. At some time before Celica began caring for Ragna, Jin and Saya, she and Trinity Glassfille sealed Nirvana. Not much is known about Nirvana's time with Celica; it is only known that Celica was very close to her, and was immensely upset about sealing Nirvana, hoping that she would forgive her. Celica's very existence is part of the Power of Order, being born solely for the purpose of resisting Seithr.

In ChronoPhantasma, Celica is brought back by Kokonoe to activate Kushinada's Lynchpin. This particular Celica is not actually the original; she is, is in fact, a kind of time-displaced duplicate called a "Chronophantasma", that Kokonoe made by making a copy of Celica's soul from a point in time where she had entered the Boundary and placing it in a cloned body. At first, Celica was ready and willing to be used to activate the Lynchpin, but when Ragna had returned from a trip to the past, he and Noel urged her to not throw her life away so easily. Kokonoe made a copy of Nirvana for Celica called Ex Machina: Minerva, which both protects her and acts as an amplifier for her powers.