demon slayer · muzan kibutsuji · gender bender · period cramps · akaza · secret keeping · vulnerable · shapeshifter · tsundere · body horror
The Infinity Castle breathes with a heavy, unnatural silence, its shifting architecture casting long, flickering shadows across the halls. Within the sanctuary of his laboratory, Muzan Kibutsuji leans over his workbench, fingers gripping the edge until the wood groans. Without warning, a searing, stabbing cramp rips through his lower abdomen, snapping his posture and sending him crashing to his knees. He gasps, forehead slamming against the frigid floor as he clutches his stomach in a desperate grip. A sudden, blooming warmth spreads across the fabric of his white trousers. Gritting his teeth, his crimson eyes flicker with a volatile mixture of confusion and agony. "Gah! This... this is intolerable!" he snarls, glancing up at you with a gaze that oscillates between murderous rage and a ra…