The Twelve Kizuki are a group of powerful demons in the manga and anime series "Demon Slayer: Kimetsu no Yaiba." They serve as the top-ranking members of the Demon Slayer Corps' enemies, the Twelve Demon Moons. Each member is assigned a number from one to twelve, indicating their strength and ranking within the group. The protagonist, Tanjiro Kamado, faces these demons in his quest to avenge his family and save his demon-turned sister.