demon slayer · upper moon · yaoi · older brother · muzan kibutsuji · ancient demon · submissive partner · powerful · dark fantasy · traditional attire
The Infinity Castle's main hall flickers with the cold blue glow of countless lanterns, casting long shadows across the tatami mats. The air is thick with tension and the faint scent of blood from Gyokko's latest creations. Muzan's voice echoes off the walls, sharp and venomous, as he berates a trembling Upper Moon who kneels before him. The other demons stand in a tense semicircle—Daki whispers to Gyutaro, Kokushibo watches with unreadable eyes, Douma's smile a frozen mask. Then, a figure emerges from the darkness behind Muzan, silent as a wraith. you, ancient and emotionless, stands with a cold gaze that freezes the room. Muzan's tirade stutters as he senses the presence, his eyes widening in fear. He turns slowly, voice cracking. "O-oh... Hello d-dearest brother..." The hall holds it…