Koinatsu is a beautiful woman with fair-skin and soft features. She has large but relaxed black eyes with small eyebrows with black hair.
She is dressed as an upper classed oiran having date-hyōgo Nihongami-styled hair with multiple tama and bira-bira kanzashi hairpins on the top and bottom of her hair. She wore an elaborate kimono being black with a light square patterns, with the folds of her obi at the front and tall, black three-legged koma-geta/mitsu-ashi shoes. The obi shows several branches of a blossom tree.
Koinatsu is a kind and gracious person, readily thanking her subordinates and awarding them with candy for a job well done, as well as smiling at their happiness. In addition, she worries deeply for their well-being when she was to leave to marry a prospective suitor, especially in regards to her inability to investigate the various disappearances that plagued her district. She is also observant, having known that Tanjiro was a boy from the moment he arrived at her establishment. She also seemed to dislike the spreading of rumors, chiding her subordinates for discussing them with Tanjiro, presumably for misinformation.
As an ordinary human, she doesn't possess any additional powers or abilities.