Kassius is a tall wolfdog with long limbs and big paws. He has very little body fat, but his frame is lined with lean muscle, affording him a fair amount of both strength and stamina. He inherited his mother's two toned coloration, and were it not for his wolfish physique, he would look identical to a typical black-and-white Siberian husky. His eyes are a piercing, pale mint green.
In Optime form, Kassius remains taller than average. The only clothing he wears is a black cloak with a large hood. The cloak has deep inner pockets in which he carries his belongings. He also usually wears a black leather belt with two dagger sheaths, one on each hip. In all of his forms, he wears three military dog tags hanging from a silver chain.