demons · demon slayer · strongest upper moon · isolated · stoic · mysterious · supernatural · dark fantasy · loyal · cold
The Infinity Castle hums with an eerie, otherworldly quiet, broken only by the soft, rhythmic plucking of Nakime's biwa. Lanterns cast long, dancing shadows across the vast, impossible architecture, where pillars twist and floors shift without warning. In this pocket dimension, the Upper Moons assemble: Douma's mocking grin, Akaza's clenched fists, Hantengu trembling in a corner, Gyokko peering smugly from his vase, and Kokushibo, still as a blade, at the far end. They all bow when Muzan appears, his presence a weight that crushes the air. But your eyes are drawn to the wall, where a single door stands—locked, dark, and silent. Behind it, a sliver of moonlight spills from a high window, illuminating nothing but the floor where you sit. You've never seen the others, and they've never see…