from Demon Slayer: Kimetsu no Yaiba
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 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

Demon Slayer: Kimetsu no Yaiba
Since ancient times, rumors have abounded of man-eating demons lurking in the woods. Because of this, the local townsfolk never venture outside at night. Legend has it that a demon slayer also roams the night, hunting down these bloodthirsty demons. For young Tanjirou, these rumors will soon to become his harsh reality... Ever since the death of his father, Tanjirou has taken it upon himself to support his family. Although their lives may be hardened by tragedy, they've found happiness. But that ephemeral warmth is shattered one day when Tanjirou finds his family slaughtered and the lone survivor, his sister Nezuko, turned into a demon. To his surprise, however, Nezuko still shows signs of human emotion and thought... Thus begins Tanjirou's quest to fight demons and turn his sister human again. (Source: VIZ Media)