Akira serves as Soji Okita's double within the substitute Shinsengumi unit, adopting the deceased captain's identity after accepting an offer to avoid execution. Her life prior to becoming a convict is unspecified. Performing Shinsengumi captain duties requires her to maintain a male disguise. She acts as the unit's kenjutsu instructor, demonstrating high competence in swordsmanship and academics alongside a disciplined work ethic and consistent physical training.

Her appearance features pale skin and long white hair with pink accents, tied in a ponytail using a white and pink ribbon. She wears a black kosode over a white shitagi, a white hakama-himo on black hakama, white tabi, and white zori sandals with pink straps. White hand guards with pink highlights complete her attire. Her sword possesses a pink scabbard, black handle wrap, and golden hand guard and butt-cap.

For an infiltration mission at the Yoshidaya in the red-light district, she adopts the geisha alias Ikumatsu, referencing the historical name later used by Kido Matsuko, wife of Kogoro Katsura. A flashback to a Kutani workshop incident shows her killing four attackers attempting to assault her, using a concealed dagger.

A spin-off comic provides additional backstory, depicting her as a university girl from the present era who reincarnated into the Bakumatsu period; this reincarnation element is specific to the spin-off media. Her relationships include an association with Kogoro Katsura, though the nature and extent of their connection beyond operational contexts remains undetailed.