Hanna Mikage is a first-year high school student and established WIXOSS player, frequently contributing to magazines and online message boards. She possesses long blonde hair and wears blue square-rimmed glasses. Her personality is calculating and blunt, often starting sentences with a summarizing word before elaborating. She attends the same school as Suzuko Homura.

Hanna's younger brother, Yuuto Mikage, died in a childhood accident. Repressed trauma prevents her from remembering the specifics, driving her participation in Selector Battles to retrieve these lost memories. Her LRIG is Nanashi, whom she initially addresses respectfully.

During Lostorage incited WIXOSS, Hanna encounters Suzuko early and pressures her for battles. They later collaborate to investigate the "Bookmaker" behind the Selector system. Hanna trains Suzuko in WIXOSS strategy in exchange for specialty sweets, bonding over shared experiences of loss; Suzuko reveals her mother's death, and Hanna confides about Yuuto.

Hanna eventually collects five gold coins through battles, reclaiming her memories of Yuuto's death. She recalls taking him to an unfinished apartment building to play hide-and-seek, where he fell. She blamed herself for not finding him sooner and for choosing the location. This traumatic memory triggers a severe mental breakdown, causing her to isolate in her room, skip school, and avoid her older sister.

Suzuko repeatedly visits Hanna, bringing homemade cakes. Hanna's older sister eventually intervenes, comforting her and emphasizing Yuuto's death was an accident, not her fault. She acknowledges Hanna's efforts to recover the memories for Yuuto's sake, aiding Hanna's recovery.

After regaining emotional stability, Hanna reconnects with Suzuko, who expresses gratitude for their friendship. Hanna reflects on her past fixation, deciding to focus on moving forward. She reconciles with her older sister, sharing a resolve to look toward the future.

Subsequently, Hanna researches and writes articles about the truth and history of Selector Battles. She encounters Dona (inhabiting Shohei Shirai's body) and reassures her about Suzuko's strength. Hanna continues her writing work with a more positive outlook, documenting the system's realities while building a life beyond her trauma.

Her relationship with Nanashi deteriorates after the memory retrieval; Nanashi reveals a sadistic nature, mocking Hanna's despair before disappearing. Hanna's bond with Suzuko deepens from rivalry to genuine friendship, crucial to her recovery. Her older sister provides critical emotional support, helping her overcome guilt.