Hailing from Lance Village on the floating continent of Ys, Lilia survived a terminal childhood illness after priest Keith revived her using monster-derived life energy. This infusion left demonic blood in her veins, granting immunity to petrification curses that affected others.

She first encountered Adol Christin when he arrived unconscious on Ys, nursing him to health. After Adol secured medicine to cure her illness, she developed deep affection for him—feelings that intensified when he rescued her from fearful villagers who imprisoned her over her monstrous ties.

Later abducted by priest Dalles to the Temple of Salmon, Lilia witnessed others petrified by his curse while remaining unharmed. Keith revealed her survival and immunity depended on her monster blood, warning that aiding goddesses Feena and Reah—who sought to erase magic—would kill her. Despite this, she chose to support Adol and the goddesses.

During the final battle against demon god Darm, Lilia endured agony due to her lineage but used a silver harmonica to restore Adol’s sanity after darkness consumed him. Absorbed as Darm’s vessel, she sensed the sorrow within the demons and Darm himself, weakening the entity and enabling Adol’s victory. Her self-sacrifice ensured Darm’s defeat but caused her disappearance.

The OVA *Ys II: Castle in the Heavens* expanded her role, showing her active participation beyond Lance Village, including captivity at Salmon Temple. Non-canonical spin-offs like *Ys IV: Mask of the Sun* and *Ys IV: The Dawn of Ys* briefly depict her pursuing Adol across Celceta and Esteria.

Adol departed Ys for further adventures after these events, leaving Lilia behind. Her unrequited feelings and quiet farewell defined her poignant narrative arc.