Miller has pale skin and long black hair tied in a low ponytail, with a curved ahoge (a single stray strand) on top of his head. His face and arms are covered in scars, and the upper part of his face is obscured, leaving only his right eye visible. He wears a white shirt under a black jacket with torn sleeves, along with a black bandolier. Occasionally, Miller wears a necklace with a Marty (a decorative tool) attached. His outfit is completed with frayed black pants and black boots. His eyes can turn a dark blue, emitting bright blue flames similar to a Marty. Miller's transformed state is relatively similar to his current form, but his face is completely hidden, revealing multiple blue eyes and a large mouth with sharp teeth. His hands turn into large black claws. Miller is quite aggressive, shouting at Skary throughout "Machine Girl" for no reason. He even goes as far as to hurt him by pushing him or hitting him over the head with a spiked baseball bat.