Phoena is the central heroine of the anime Chain Chronicle: The Light of Haecceitas and the keeper of the Chain Chronicle, a mysterious book that records the history of the world. She is a young woman with blue hair usually worn in a long side braid and violet eyes, and her appearance includes winter clothing, most notably a fur-trimmed coat. At the beginning of the story she is fleeing an attack by the Black Army when she is rescued by the protagonist Yuri, and she has no memory of her own identity, a condition of retrograde amnesia. It is eventually revealed that she is the daughter of the Black King and that she originates from a continent north of Yggdra, the land where the conflict takes place.

In personality, Phoena is gentle, sincere, and kind-hearted, and she treats others with warmth even in difficult circumstances. She is somewhat naive and can seem absent-minded, but she is also perceptive and able to see to the heart of a situation, and she possesses a strong inner core. Because she carries the Chronicle, she becomes the primary target of the Black Army, whose leader seeks to use the book to erase the world and rewrite existence into nothingness. Her main motivations are to recover her lost memories, understand the true nature of the book entrusted to her, and protect the people who have protected her. She does not wish for conflict or unnecessary suffering, and she carries a quiet sorrow because her very existence draws danger toward those around her. Among her companions, she is also known for being a very poor cook, something those close to her try to gently avoid.

Within the story, Phoena serves as the emotional center of the Volunteer Army, the group gathered by Yuri to oppose the Black King. Although she is not a frontline fighter, she supports her allies in battle as a Chronicler-Class Cleric, using healing abilities that become stronger and reach further than ordinary healing. Her link to the Chain Chronicle gives her a special connection to the world's history, and over time she learns to harness the power of the book to aid her companions. Her role is central to the entire conflict because the Chronicle is the key to the world's survival or destruction.

Her most important relationship is with Yuri, who saves her at the start of the journey and becomes her protector and closest trusted companion. She also shares a close, sisterly bond with the fairy Pirika, who acts as a guide and friend to the group. By contrast, her father, the Black King, is the principal antagonist, and her family connection to him becomes a major source of personal and narrative conflict, forcing her to confront painful truths about her origin while still choosing to stand against him.

Over the course of the story, Phoena develops from a helpless amnesiac into a determined guardian of the world's history. She grows more confident in her abilities and more certain of her convictions, eventually facing her heritage directly in order to prevent the total erasure of existence. Her character arc is defined by her choice to embrace the bonds she has formed and to use the power of the Chronicle to protect the future rather than allow it to be used for destruction.