Yomi hailed from a clan bound by centuries of devotion to Mōryō, a malevolent demonic force, honing forbidden medical ninjutsu steeped in shadow. An ancestor’s past ambition to wield Mōryō’s power for global conquest ended when Miroku sealed the entity away. As a medical-nin, Yomi wielded corrosive dark chakra to enhance allies’ physical prowess and prolong their combat vitality, his mastery culminating in a grotesque ritual: slicing his own chest open with a scalpel to temporarily harbor Mōryō’s spirit. The wound closed seamlessly with stitches, no blood spilling—only an abyss beneath his skin. His visage blended sharp features—pale complexion, ink-black hair cascading past his shoulders, a trimmed goatee, and piercing sand-colored eyes—with austere attire: a gray uniform beneath a sweeping black trench coat. Prolonged possession by Mōryō eroded his form, leaving him skeletal and weathered. The jagged stitched scar spanning his chest served as both conduit and testament to his pact. Yomi governed with icy pragmatism, sacrificing underlings like Gitai without hesitation to advance his objectives. He addressed allies with contemptuous epithets like "wretched fools," his calm demeanor laced with disdain. Even facing mortality, he clung to the certainty that his schemes would outlive him. To resurrect Mōryō, Yomi infused the Gang of Four with venomous dark chakra serpents, shattering the demon’s prison. He surrendered his body as a temporary vessel while plotting to reclaim Mōryō’s true form. When Shion moved to reseal the entity, Yomi intercepted her, only for Mōryō to rupture violently from his body, leaving him lifeless. His remains vanished into molten lava during the ensuing cataclysm. His name, meaning "underworld," mirrored his tether to darkness. Unlike most film antagonists, he never crossed paths with Naruto Uzumaki. Combat skills included blinding speed, immunity to pain, and a shock wave technique mirroring the Shrine Seal, which he unleashed to demolish Mōryō’s tomb.