Yukito Yanagi grew up in a mainland Japanese welfare facility after his father Makoto Yanagi's death when he was five. His relocation followed Makoto's final instructions, enforced by guardian Sanji Inou, though the reasons eluded Yukito. A childhood incident revealed his innate water manipulation ability, which spiraled out of control and endangered other children. Fearing he might harm others, he distanced himself while secretly craving connection. At fifteen, after middle school graduation, Inou summoned him back to his birthplace—the seven islands of Ayakajima. He was retrieved by Jingi Sagawa, his father's former disciple and Yukito's own childhood friend. Returning to Ayakajima, Yukito discovered the islands harbored spiritual entities called Mitama, including malevolent Ara-mitama. He learned of his heritage as a "Ley Master," tasked with maintaining spiritual balance and protecting the islands. Training under Jingi, he encountered Makoto's other disciples: Haruaki Kurama, head priest of Kasen Shrine, and Aka Ibuki, director of Ayaka Security. Their opposing philosophies on handling Ara-mitama mirrored unresolved conflicts from their time under Makoto. Yukito wrestled with mastering his potent but volatile water-based powers. Haunted by past accidents, he hesitated to use them even during Ara-mitama pacification missions. Gradually, he bonded with peers: Kurama's disciples Chatarō Fukuwake and Yako Amano, and Ibuki's associate Ibara Ichijō. A critical revelation unfolded: Yukito was the human incarnation of Ayakajima's life-giving water dragon, essential to the islands' stability. Makoto had sacrificed his life a decade earlier to seal a catastrophic volcanic eruption caused by a destructive fire dragon. Sending Yukito away shielded him until he could control his draconic power. When the fire dragon reawakened, Yukito failed to unleash his full strength despite defending others. Jingi, long aware of his secret, performed an ancient spell requiring the caster's life to restore the water dragon's power. Over Yukito's protests, Jingi sacrificed himself. Empowered, Yukito transformed into the water dragon, confronted the fire dragon, and flooded the volcanic crater. This transformation marked his acceptance of identity and destiny, shifting from fear and isolation toward embracing his role as Ayakajima's protector and the bonds forged there.