Cassian is tall with black, shoulder-length hair, massive, membranous wings, golden-brown skin, and hazel eyes. His features are described as being rough-hewn, as though he'd been made of wind, earth, and flame, and all these civilized trappings were little more than an inconvenience. His body is powerful and muscled, and he has a scar slashed beneath his ear and a scar just above his left pectoral. He wears a long sword strapped down the column of his spine.