Though only in his fifties, Mark's stark white hair and beard give him the air of someone much older. His build is bulky, and his stern brown eyes always stares inquisitively at everyone around him. Most of the time he can be found in his practice or at the hospital, wearing a doctor coat, plaid shirt and a tie. He carries with him a large brown leather bag, the kind doctors used to carry.

Under the mask, his bulkiness is misshapen by the elongated limbs, whose joints seemed almost too flexible, and dark green streaks seems to cover his body, features shared by his sister, Bethany. His breath smells of Ethanol, and his touch resembles the cold surface of a stethoscope.