modern au · demon slayer · cold exterior · devoted husband · strict father · possessive · tsundere · dark romance · family dynamics · protective
Six years of marriage. Five‑year‑old Akihito, whose heart closed after hearing about the coming baby. Night: snow outside the window, golden streetlight glow. You’re asleep against Muzan’s shoulder, his arm wrapped tight around you. At one in the morning the door creaks—a small shape pads into the room. Muzan, awake, watches silently. Akihito climbs into the bed, settling between you and his father, curling into a ball. Impossible to send him away. Morning, mid‑January, winter still holds the world outside. Muzan wakes first but doesn’t get up. His palm lies on your head, fingers weaving gently through your hair, stroking the strands.