Fana is a complex character whose identity is defined by tragedy and a dual existence. Originating as a human orphan from the Diamond Kingdom, she was forced into brutal military experiments designed to enhance magical power. Her life changed forever when, after a near-death experience, her body became the vessel for the soul of an elf also named Fana, who was killed in a massacre five hundred years prior. This forbidden reincarnation transformed her into a core member of the terrorist organization the Eye of the Midnight Sun, specifically one of its three strongest warriors, the Third Eye, bearing the epithet of "Hatred".

Fana's personality is fractured due to the two souls inhabiting a single body. In her original human form, she is described as a kind, soft-spoken, and caring individual who shares a deep bond with her fellow experiment subject, Mars. However, as a vessel for the elf's vengeful spirit, her exterior is placid but hides a deeply unstable and hateful nature. Under the influence of the forbidden magic, she becomes ruthless, quick to anger, and merciless toward anyone she deems her enemy, driven by an ancient racial hatred against the humans of the Clover Kingdom. Despite this, she remains fiercely loyal to her comrades in the Eye of the Midnight Sun, particularly to the leader, Patolli.

Her primary motivation throughout most of the story is vengeance. The elf soul within her seeks to annihilate the humans she believes betrayed and slaughtered her people, allowing her to be easily manipulated by the main antagonist, Patolli, who orchestrated the reincarnation. This goal places her in direct conflict with the protagonist, Asta, and the Magic Knights. Her role shifts from a powerful antagonist to a victim in need of salvation, as other characters recognize the tragedy of her situation.

Key relationships define her journey. Her most significant bond is with Mars, a fellow survivor of the Diamond Kingdom's experiments. They share a childhood promise to explore the world together, and it is Mars's unwavering love and determination that ultimately breaks the elf's control over her. Within the Eye of the Midnight Sun, she works alongside her Third Eye compatriots, Vetto and Rhya, showing complete devotion to Patolli, whom she considers a savior. Fanzell Kruger, her former swordsmanship instructor from the Diamond Kingdom, also plays a crucial role in her eventual rehabilitation.

Fana undergoes significant development, transitioning from a feared terrorist to a liberated survivor. During the battle in the Witches' Forest, her confrontation with Mars and Asta causes the conflicting memories of both souls to surface, leading her to attempt a suicidal, self-destructive attack. Asta's anti-magic swords and Mars's emotional plea destroy the "third eye" that symbolized the elf's hatred, freeing the human Fana's consciousness. Later, the elf soul is completely reincarnated into an artificial, younger body, allowing the human Fana to finally live in peace. The original human Fana decides to leave both the Eye of the Midnight Sun and the Diamond Kingdom behind, choosing to live a quiet life while Mars works to change their homeland for the better.

Before being freed, Fana possessed immense combat abilities, considered even greater than the organization's leader in terms of raw power. As a member of the Third Eye, she could summon and control Salamander, the powerful fire spirit, granting her devastating offensive capabilities. Due to the Diamond Kingdom's experiments, which fused her grimoire with Mars's, she wields dual magic attributes: fire magic and crystal magic. Her fire can reach temperatures high enough to counter mercury magic, and she can generate massive crystal structures for both offense and defense. She also possesses potent healing magic with phoenix-like properties, allowing her to regenerate from grievous wounds. After the elf soul's complete reincarnation into a new body, Fana loses Salamander but retains an enhanced version of her fire recovery magic, which grants her near-immortality.