Fyana originates as Proto-One, the first genetically engineered Perfect Soldier created by the Melkian military. Extensive experimentation involving special substances and gene manipulation suppressed most emotions while enhancing combat instincts and physical capabilities, designing her as a living weapon. Her initial awakening occurs during a mission on the asteroid Lido, where Chirico Cuvie witnesses her containment pod, forging an immediate and lasting psychic connection between them. Following the cancellation of the Perfect Soldier project, she becomes an unfinished prototype lacking the full capabilities of subsequent models like Ypsilon.

Abandoned by the military, she resurfaces in Uoodo City operating as the mysterious fugitive "Phantom Lady." Chirico later names her Fyana, marking the start of her transition from weapon to an individual developing genuine emotions and personal agency. A recurring survival challenge stems from her dependency on jijirium radiation for periodic re-energization, requiring access to specific facilities to maintain physical stability.

In "The Last Red Shoulder," Fyana is held at Yoran Pailsen's compound alongside the newly activated Perfect Soldier Ypsilon. Tasked with mentoring him, she introduces him to the natural world and attempts to instill empathy, such as teaching appreciation for living creatures. This contrasts sharply with the Secret Society's intent to weaponize Ypsilon, causing friction when her methods trigger his violent instincts. Her interactions with Pailsen reveal internal conflict; she questions the ethics of creating emotionally aware soldiers, citing her own struggles with doubt and identity. Pailsen observes that her encounter with Chirico fundamentally altered her development, igniting a capacity for love and desire for human existence.

During Chirico's assault on the compound, Fyana intervenes to stop Ypsilon from killing him. In a critical moment, she kisses Ypsilon to halt his lethal attack, demonstrating compassion and reinforcing her rejection of weaponized programming. She subsequently flees the compound with Ypsilon, protecting him from the Secret Society's manipulations.

Fyana's relationship with Chirico drives her arc, inspiring her defection from the Secret Society. They unite as fugitives, and her evolution culminates in a mutual decision to enter cryogenic sleep, awaiting a peaceful future together. This conclusion underscores her complete transition from military asset to an autonomous individual defined by loyalty, love, and the pursuit of humanity.