Kohaku

Kohaku (琥こ珀はく, "Amber") is Sango's younger brother. He is also a yōkai taijiya, like his older sister and their father, from the Yōkai taijiya village. He was manipulated by Naraku through most of the time during the Shikon Jewel's return to the feudal era, and he was only kept alive by the jewel shard in the back of his neck. Many years following Naraku's death and the Jewel's disappearance, he had become the leader of the newly reestablished Demon Slayers.