Kiriya has light, pale skin and large eyes. He has the same hairstyle as the rest of his siblings; a blunt bob with a fringe covering his eyebrows, colored black. As he was raised as a girl, he takes on a more feminine appearance during his first appearance.
During the Final Selection test, Kiriya wears a purple kimono with patterned flowers and a green obi. His head is adorned with a wisteria headpiece.
Later on in the manga, he wears a black kimono with a a long white kimono jacket, reminiscence of his father.
During his first appearance in the series during the Final Selection test, Kiriya portrays himself to be polite, competent, and somewhat emotionally detached having calmly and politely greeted the trainees in sync with his sister, professionally explaining the details regarding the test. He is somewhat unfazed when Genya Shinazugawa roughly manhandles of his sister.
Later, upon his father, mother and sisters' deaths, Kiriya shows an entirely different side to himself, displaying his capabilities as a leader. He immediately jumps into his new position and organizes himself to monitor and command the Demon Slayers on their attack against Muzan Kibutsuji and his Demon Moons, despite just losing half of his family and not even properly having the time to mourn them. He shows more mental fortitude and emotional strength in comparison to his younger sisters, who momentarily broke into tears in grief.
However, once his plan results in the slaughter of many Demon Slayers, Kiriya breaks under stress and stops giving orders, much to his sisters' dismay. He is able to pull himself back together after Kanata slaps him.
Kiriya was born to Kagaya Ubuyashiki and Amane Ubuyashiki as their third child and only son of five children. He was born after his two older twin sisters and before his two younger twin sisters. As the sole son of the family, he becomes the male heir, the next head of the Ubuyashiki family and the first in line to inherit his father's position as commander of the Demon Slaying Corps.
From the time he was born, his parents raised him up as a girl since they believed that young boys were weak and frail.
Abilities and Powers
- Leadership Skills - Much like his father, Kiriya displays advanced skills in leading and commanding an army into battle despite his young age. He is able to immediately take command of the Demon Slayer Corps's command structure and assist the Pillars as logistical support, guiding them into battle.
- Intuition - Similar to his father and his ancestors, Kiriya has a high, almost prophetic intuition, being able make accurate guesses and hypotheses that were often proven right through feeling alone.
- Extraordinary Memory - Kiriya has shown extremely good memory. He and his sisters are able to map out and memorize the nearly constantly changing Dimensional Infinity Fortress, creating accurate maps to navigate and guide the Pillars through it in real time.
- Kiriya shares the same Japanese and English voice actresses with Madoka Kaname from Madoka Magica.