Kiriya Ubuyashiki is the only son and middle child of Kagaya Ubuyashiki and the head of the Ubuyashiki Household. After his father's passing, he leads the Demon Slayer Corps as the 98th and final leader. 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 uchikake kimono with patterned flowers and a green obi, supported with a white obiage and indigo obijime along with a white juban under everything. His head is adorned with a wisteria headpiece. Later on in the manga, after he becomes the leader of the Demon Slayer Corps, he wears a black kimono with a long white haori that's reminiscent 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 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 Twelve Kizuki, 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.