A skilled doctor and prosthetics maker, Jukai shapes Hyakkimaru’s early life through technical mastery and haunted morality. Once a soldier under a cruel lord, he committed wartime atrocities—crucifying prisoners among them. The traumatic death of a prisoner’s wife during an execution shattered his psyche, driving him to attempt suicide. Surviving, he atoned by crafting prosthetics from deceased children’s remains, blending healing magic with alchemy—a testament to his technical skill and moral complexity. Discovering infant Hyakkimaru—born limbless and senseless from a demonic pact—Jukai became his guardian. He forged prosthetics and combat skills for the boy, nurturing a paternal bond marred by guilt over imparting violence to one blind to its consequences. This tension peaked as Hyakkimaru began slaying demons to reclaim his body, heralding his independence. His past resurfaces through Kaname, a former assistant whose father he executed. Though Jukai crafted a prosthetic leg to aid him, Kaname spurned the offering upon uncovering Jukai’s history, fleeing—a stark reminder of war’s enduring scars and elusive forgiveness. Tormented by nightmares of his brutality and a relentless hunger for redemption, Jukai’s farewell to Hyakkimaru spoke volumes through touch—their bond transcending the youth’s sensory void. Visual echoes of a gray aura tinged with blue mirror his perpetual sorrow. Diverging from the manga’s benevolent healer with scant history, the anime deepens Jukai’s narrative—exposing his military past, Kaname’s betrayal, and the psychological weight of his sins. These layers sculpt him into a tragic figure, forever clawing toward redemption through regret-steeped atonement.