Aoi is a young woman of average height and pale skin complexion. She has large, deep blue eyes that fade to a lighter blue at the bottom, along with white rectangular pupils. She has straight black hair with a parted fringe and twin-tails. She has dark, thin, and arched eyebrows which are usually furrowed due to the frown that she often has on her face. She wears two white butterfly ornaments that keeps her twin-tails in place. They have a light indigo-colored trim on the outer side of the wings, and are decorated with light turquoise-colored speckled spots. Aoi wears the standard Demon Slayer uniform with the addition of a white nurse dress on top of it, with a blue sash around her waist. Her uniform is tinted slightly blue, along with pair of zōri with blue straps and white tabi socks. The uniform consisted of a button-up jacket with a stand-up collar and long sleeves, featuring silver buttons, a shirt pocket on the left breast, and the kanji for Destroy (滅めつ, Metsu?) engraved on the back of the uniform. Beneath the jacket, she wore a white long-sleeved collared undershirt, and her outfit was fastened at the waist with the standard white belt. She wore traditional tattsuke-hakama pants matching the blue color tone of her uniform. Aoi is tough, uncompromising, strict, and serious, displaying an efficient and no-nonsensical attitude nearly at all times. While performing her duties in the Butterfly Mansion, she is effective and proactive, evident when she quickly demands a complaining Zenitsu to silence himself and take his medication; going so far as to demand he does not complain to her when he does not heal, despite his reluctance due to its bad taste. Aoi's personality is somewhat similar to that of a younger Shinobu Kocho, being loud, volatile, and open. She often appears angry, generally displaying how she feels very clearly. However, she does occasionally express more tender emotions such as declaring her enjoyment of the time spent with the trio when they were at the Mansion,[5] looking openly surprised at Tanjiro's reassurance towards her,[6] and bursting into tears when discussing Inosuke's serious injuries.[7] Aoi harbors insecurity over her inability to be an effective Demon Slayer, stating that her survival of Final Selection was due to luck and deeming herself a coward for her failure to fight in battle due to her immense fear of combat. Despite her somewhat gruff demeanor, she is very kind and caring, doing her best to help the Demon Slayers that come to the Butterfly Mansion for rehabilitation training.[8] Aoi is shown to be rather reserved, as shown when Tanjiro asks what she would do to show someone who thinks he is alone that he isn't actually alone, she bluntly states that she wouldn't know and that she would prefer to be left alone. She’s 16 years old, she is 5’4, and her favorite food is tempura.