Leon is depicted as a morbidly obese, unspecified humanoid-like creature with grey skin and white hair. He is shown to be in extremely poor health, most likely as a result of his obesity, relying on a scooter to get around and having difficulty breathing without a cannister of oxygen nearby.
It is heavily implied by both Randall and Leon himself that Leon is a serial killer. Leon also states that there have been unsolved murders in the building, donning a sinister grin immediately afterwards. Randall later mentions that Leon has a "murder nest".
- When Leon surprises Randall from behind, Randall turns around and hits him with an axe. Leon simply removes the axe from his own shoulder and does not seem to have been hurt.