Avrora Florestina emerged as one of twelve artificial humanoid Kaleid Bloods forged from the Fourth Primogenitor’s divided essence. Charged with guarding the enigmatic "Root," she bore long blonde hair, azure eyes, and a fragile disposition, hesitant to unleash her vampiric might, haunted by their catastrophic potential. Sealed within the Fairy’s Coffin ruins, her stasis fractured when the Black Death Emperor Front attacked, compelling Kojou Akatsuki to sacrifice himself for her and his sister Nagisa.

To resurrect Kojou, Avrora surrendered her fourth and fifth ribs, binding him as her blood servant and intertwining their destinies. Gradually, she grew devoted to him, captivated by his altruism and tenacity. When Root awakened within Nagisa, Avrora merged with the entity to halt its rampage, transferring her Fourth Primogenitor authority to Kojou and demanding he eradicate her with a ritual stake. Nagisa preserved Avrora’s fading consciousness within herself, forging a shared existence as symbiotic sisters.

Kojou later revived Avrora using a ring fused with his blood and ribs, reversing their bond to make her his dependent. Though stripped of her Kaleid Blood dominion, she retained command over Alrescha-Glacies, her twelfth familiar—a glacial mermaid entity wielding sub-absolute-zero frost. After her doll-body’s destruction, her consciousness migrated into Hektos, a former familiar.

Her defining connections include a mentor-protégé bond maturing into marriage with Kojou, whom she recognizes as her heir, and a protective symbiosis with Nagisa. Historical archives note her name, gifted by Liana Caruana, drew from Sleeping Beauty lore, while personal eccentricities encompass a fondness for tri-flavored ice cream and difficulty fastening shirts unaided. Her original vessel remains conserved in MAR’s "Sleeping Princess" research archive.