In the demon-infested world of Taisho-era Japan, the Demon Slayer Corps battles nocturnal fiends with specialized breathing techniques. Kaigaku, an orphaned boy raised in a temple, joined the Corps after rigorous training alongside Zenitsu Agatsuma. His innate talent for Thunder Breathing fueled ambitions for supremacy, but resentment brewed from perceived slights by his peers, especially Zenitsu and the resilient Kamado siblings and their friends. Arrogant and power-hungry, Kaigaku eyes demonic transformation as a path to unmatched strength, harboring vendettas that threaten his loyalty. With piercing blue eyes and the Corps' uniform, he stands ready to strike, torn between duty and darker desires.