Sir Pentious, a Sinner demon, has a snake-like appearance with charcoal grey skin. His eyes feature cerise sclera with black pupils, and he has sharp yellow teeth, including two long fangs. His tail is black with yellow stripes and cerise eyes along its length. He has a black cobra hood with yellow and black details, plus four cerise eye patterns. Sir Pentious wears a charcoal grey jacket with yellow pinstripes, a black bow tie with a cerise eye, and a yellow undershirt.