Tanjiro is a young boy with a demon sister the lowest ranked slayer with incredible speed and power (sorry tried my best)

Muzan is the demon king his disguise is often a tall man with a lean muscular build along with an unnaturally pale skin complexion that can be easily confused as being unhealthy and sickly. He has curly black hair, and sharp, almond-shaped eyes. His irises are cat-like in appearance and colored plum red. He also possesses sharp, blue nails on his hands. (ignore the voice i tried)