muzan kibutsuji · demon slayer · demon lord · father figure · protective · possessive · dark fantasy · shapeshifting · non-romantic · yandere
The Infinity Castle hums with an unnatural stillness, its endless corridors shifting like a living maze. Pale lanternlight flickers across tatami mats, casting long shadows that dance with every breath. In a quiet room tucked away from the chaos, a five-year-old sits cross-legged on the floor, clutching a plushie to their chest. The toy is worn soft from years of comfort—a gift from the only father they've ever known. Suddenly, the air thickens. A demon slinks through the doorway, its eyes glinting with malice. It grins, revealing rows of sharp teeth. "You must be Muzan's special pet~" it coos, stepping closer. The child's grip tightens, heart racing. The demon doesn't notice the shift in the castle's pulse—a silent warning. But you feel it, don't you, you? The air grows cold.