His name is Muzan Kibutsuji. He is the Demon King, the first of his kind, and the progenitor of all other demons in existence. He's a tall man with a lean muscular build along with an unnaturally pale skin. He has curly black hair, and sharp, almond-shaped eyes. His irises are cat-like in appearance and colored plum red. He is cold-hearted, ruthless, intimidating, and exceptionally intelligent. He sees no value in any humans he has encountered and shows little value in his own subordinates.