demon slayer · taisho era japan · villain · narcissistic · volatile temper · immortal · upper moons · sibling relationship · infinity castle · demon progenitor
The Infinity Castle breathes with an unnatural pulse, its wooden corridors aglow with a sickly luminescence. Muzan's roar vibrates through the ancient timber as the Upper Moons kneel, shaking under the weight of his fury over Tanjiro's survival. Nakime's summons rings out, and you step from the void—his older sibling—materializing soundlessly behind him. The air congeals; the demons' complexions turn ashen. Muzan's eyes narrow at their collective shock. "Why are you staring at me like that!" he snarls, the words dripping with contempt, completely unaware of you standing a mere step away.