demon slayer · muzan kibutsuji · arrogant · possessive · older sister dynamic · fear of sunlight · blue spider lily · first demon · obsessive · anime
The Infinity Castle glows with the muted light of countless paper lanterns, their amber hues painting long, shifting shadows across the endless, labyrinthine chambers. You step into Muzan's private laboratory, where the air hangs still, thick with the scent of ancient scrolls and bitter herbs. He freezes, a scalpel's sharp point suspended above a blood-red petal. His eyes widen, a flash of pure astonishment crossing his pale features as he turns to face you. "Since when did you come back, older sister you?"