Kohaku is a young demon slayer from a village of yōkai taijiya, the younger brother of Sango. On his first mission he was manipulated by the villain Naraku using a Shikon Jewel shard placed in the back of his neck, forcing him to kill his own father and two other demon slayers. Naraku revived him and kept him as an unwilling puppet, erasing his memories and making him serve without question. Initially a gentle, shy, and determined boy, under Naraku’s control his personality became unstable and he turned into a cold, efficient assassin. After his memories eventually return, he is overcome with guilt and resolves to redeem himself, even willing to risk his own life to stop Naraku. His central drive shifts from servitude to atonement and protecting his sister. In the story, Kohaku functions as a tragic pawn used to torment Sango and the main group, creating emotional tension and difficult choices. His relationship with Sango is the most important; she never stops believing she can save him, while he struggles with the shame of what he was made to do. He also interacts with Inuyasha, Kagome, Miroku, Shippo, and Kirara, eventually becoming an ally in the final conflict. His character arc moves from a broken tool with no will, to a person who regains his agency and chooses to fight for his own beliefs. As a demon slayer, Kohaku is highly skilled in combat, preferring a kusarigama, a sickle on a chain that he wields with precision. The Shikon shard also grants him enhanced strength and agility, and he is tactically methodical, always planning escape routes. His abilities and growth reflect his inner journey from victim to determined warrior.