"There's a bit of every artist in their work."[src]
Stelline was born on June 10, 2021, the daughter of former Blade Runner Rick Deckard and Rachael, a Nexus-7 replicant, making her the first replicant-born child. However, Rachael died as a result of Stelline's emergency caesarian-section birth.
Prior to the birth, in order to protect his daughter and partner, Deckard left them in the care of a replicant freedom group, specifically Sapper Morton and Freysa Sadeghpour. After Stelline was born, her birth records were scrambled, making it seem that the pregnancy produced twins, a boy and a girl with identical DNA, and that the girl died young of a genetic disorder.
She was processed at the Morrillcole Orphanage in San Diego. On one occasion during her time there, she was chased by a group of other orphans, who sought a toy horse she had. She hid the horse in an abandoned furnace and was beaten by the children.
By 2049, Stelline was subcontracted by the Wallace Corporation and had to be quarantined due to her health. For her work, she was confined to her chamber where she could use a "memory orb" device to construct replicant memories to structure personalities. She manipulated these via holograms that she could interact with, and would presumably ship them off to Wallace. She claimed to love birthday parties, often creating memories based on them.
On July 4, she was visited by Nexus-9 Blade Runner K, who asked her to determine the authenticity of a childhood memory of his. She examined the memory, which happened to be her own, hiding the horse at the orphanage. Tearfully, she confirmed it to be real.
Freysa soon revealed to K that he was not Rachael and Deckard's child, leading him to determine that Stelline was. K took Deckard to Stelline's lab as she interacted with a snowfall hologram. She did not recognize him, but Deckard affectionately placed his open hand on the window.