Princess Fione, daughter of Queen Aldora, belongs to the royal family ruling the kingdom where the Suicide Squad finds itself. Deeply caring for her people, she yearns to end the decades-long war ravaging the land, a conflict worsened by the betrayal of elves and beastmen. Yet extreme shyness plagues her, making her hesitant to voice opinions or challenge her mother's authoritative decrees.

Her compassion springs from childhood, forged when she secretly left the castle to befriend peasants. Witnessing their deaths in the war fueled her fierce desire to protect the vulnerable. Despite her royal status, she feels stifled under Aldora's control and is often dismissed during court discussions on kingdom strategy or prisoners.

Fione's encounter with the Suicide Squad, particularly the defiant Harley Quinn, sparks significant change. Harley's unapologetic freedom fascinates the reserved princess, highlighting Fione's own suppressed rebelliousness. Initially, she pragmatically advocates for the squad's utility, convincing her knight Cecil to retrieve them from prison against her mother's wishes. Witnessing their chaotic effectiveness firsthand emboldens her, leading to a confrontation with Harley about their similarities.

A pivotal revelation shatters her timidity: discovering her mother replaced by the manipulative Undead King. Forced to act, Fione channels Harley's fearlessness. She defiantly stands against the Undead King and its forces, including brainwashed elves and villains. Her appearance evolves, adopting stylistic elements reminiscent of Harley's.

Supported by Cecil and eventually the Suicide Squad, Fione embraces leadership in the battle to reclaim her kingdom. She openly defies the Undead King and fights to protect her subjects, culminating her journey from a passive princess to a decisive ruler risking everything for justice.