Item from Demon Slayer by Koyoharu Gotouge
A Nichirin blade fused with demon flesh — it regenerates, grows new blades from wounds, and has eyes that track opponents, making it the most terrifying weapon in the Twelve Kizuki.
Kokushibo's flesh sword is a Nichirin blade that has fused with its wielder's demon body over four hundred years. It's no longer a separate weapon — it's an extension of Kokushibo himself, growing from his hand and sharing his regeneration. This means it can't be disarmed in any meaningful sense, repairs itself mid-fight, and can sprout additional cutting edges from anywhere on its surface. The eyes embedded in the blade track opponents independently of Kokushibo's six eyes, giving him near-360-degree awareness during combat. Combined with Moon Breathing's crescent-energy multiplier, the sword creates a storm of cutting surfaces that even Hashira struggle to navigate. It's the physical embodiment of Kokushibo's fusion of human swordsmanship and demon biology — the thing his brother Yoriichi would never have become.
A katana that appears to be made of living tissue — the blade is organic, with a dark reddish hue and visible vein-like patterns running along its surface. Multiple eyes dot the blade and guard, moving independently to track targets. When damaged, the sword regenerates like demon flesh. During combat, it can extend additional blades from any point on its surface, turning a single katana into a multi-blade weapon. The tsuba (guard) resembles an eye. The overall effect is deeply unsettling — a weapon that watches you.
Also known as: Flesh Katana, Kokushibo's Blade, Living Sword