Kuina Ubuyashiki (
Kuina has features similar to the rest of her family, light, pale skin with a set of large eyes. She wears a white blunt bob with fringe covering her eyes.
Kuina is usually seen wearing a purple, flower-patterened Edo komon kimono with a white juban under it. She also wears a black obi with a white obiage under it and a pink obijime tying it. She adorns her hair with a short flower headpiece with two beads hanging off it.
Kuina displays her strong sense of loyalty and devotion to her brother as the new head of the Ubuyashiki Family and Commander of the Demon Slayer Corps, by being the one to forcefully remind him of his duties as their leader. She even resorts to physical force to remind him of this by slapping him, in order to ensure he did not break down under the stress of his responsibilities.
Kuina and Kanata were born into the Ubuyashiki family. They are the youngest children in the family.
Kuina helps her brother and sister draw a map of the Infinity Fortress.
Extraordinary Memory: During the infiltration of the Infinity Castle by the Demon Slayer Corps, Kuina displays exceptional memory and skill in map making, having successfully mapped out and memorized the entire structure, despite the castle constantly changing. She also provides real-time logistical information to the Hashira alongside her sister, aiding her brother in planning the route to Muzan Kibutsuji's location.
- Kuina was the last member of the Ubuyashiki Household revealed.
- She has good physical abilities. She's called the "slap princess", since she tends to slap people when she overreacts emotionally. Although, she ends up regretting it every time.