Flute hails from the secluded Staccato village in the kingdom of Sforzend. Unaware of her royal lineage, she lived an ordinary life until Queen Horn's protective barrier shattered, revealing her identity as the queen's daughter. This revelation coincided with a demonic assault on her village, compelling her to flee towards the capital with her childhood companion, Hamel, under orders to reunite with her mother.

Her journey sparks significant personal growth. Initially reluctant and overwhelmed by her sudden royal responsibility, she gradually accepts her role as princess. Traveling with Hamel and companions like the swordsman Trom BON and the pianist Raiel, she witnesses widespread destruction and confronts demons intent on resurrecting their sealed ruler, Kestra (Orchestra). These experiences forge her resolve to protect humanity.

A defining trait is her profound bond with Hamel. She pledges unwavering loyalty, vowing to accept him regardless of his origins. This loyalty faces a severe test upon learning he is the son of Pandora and the Demon King Chestra, inheriting demonic blood. Even after witnessing his violent transformation and actions, including killing Trom BON's father, she refuses to abandon him, asserting her commitment transcends his form.

The narrative culminates in tragedy. After defeating the demonic forces, Hamel fully embraces his heritage to become the new Demon King. To prevent catastrophe, Flute makes the agonizing decision to seal him within Pandora's Box, wielding its power despite the personal cost. The anime concludes melancholically, implying her enduring loneliness and burden, though a later temptation to reopen the box due to her love lingers.

Her character design typically features pigtails, a hat, and attire reflecting her village origins and later royal status. Her fate diverges across adaptations: the anime emphasizes sacrifice and unresolved sorrow, while the source manga offers a more optimistic resolution.