OVA
Description
Cossette d'Auvergne was an 18th-century European aristocratic girl murdered by her fiancé, the artist Marcello Orlando. He killed her and her family, seeking to eternally preserve her beauty by halting her aging. Her spirit became imprisoned within a delicate Venetian glass, while the lingering despair and vengeful grudges from these events seeped into other household glass objects, cursing them. This bound her to an otherworldly realm accessible through reflections, where she existed for centuries.

Her appearance features shoulder-length blonde hair, bright blue eyes, and pale skin, typically adorned in frilly dresses with ribbons and head scarves. This striking beauty, which first captivated Marcello, became hauntingly enchanting in her spectral form. She manifests within the glass as moving images of her life, visible to observers.

Personality-wise, Cossette exhibits a calm yet mysterious demeanor and a capacity for manipulation. After 250 years of isolation, she actively seeks liberation from her curse. This requires a willing participant to bear her murderer's punishment via a blood pact. She identifies Eiri Kurahashi, an art student and antique shop worker obsessed with her image, as the ideal candidate. Recognizing him as Marcello's reincarnation, she exploits his infatuation to forge the pact, initiating his physical and psychological torment as atonement for Marcello's sins.

As Eiri suffers, her feelings shift from vengeful manipulation to genuine conflict. Witnessing his unwavering devotion despite the agony sparks authentic affection for him, leading to profound regret for involving him in the cycle of retribution. Concurrently, another facet emerges: a sentient doppelgänger born from Marcello's final, lifelike portrait. This entity, believing itself the true Cossette, remains devoted to Marcello and views Eiri only as a vessel for his soul, creating a duality within her legacy.

Her resolution involves breaking the curse's cycle. To prevent Eiri from fully becoming Marcello and spare him further pain, she consciously chooses self-sacrifice. This act severs the blood pact, allowing her spirit peace. Her essence is subsequently reborn into Shoko Mataki, Eiri's friend harboring secret feelings for him, signifying a transcendental resolution to her centuries-long anguish.