Mule is a human-looking woman with equine features. She has equine lower legs that end in hooves and an equine tail above her ample bottom. She looks to be about age 20. She is tall and slim, with small breasts, though her limbs are sinewy and quite muscular. She has brown skin, large amber eyes and glossy black hair, which is normally worn in a pony tail, apparently to match her equine tail. She seems to like harness-like armour in variety of colours. She can speak the common tongue perfectly well but stubbornly uses certain idiosyncratic words. These might be from her native language or just mispronounced or misunderstood common. She is fond of equestrian terms. However, when she gets excited, such as in combat, she is able to produce a variety of horse noises that sound exactly like they were made by a real horse. She seems to be a slow thinker and not too bright.

Mule usually carries a bow and a quiver of arrows. She often has a lot of bags attached to her harness, enchanted for low weight but designed to look like saddle bags.

Despite her mundane appearance, Mule seems to have several magical or unusual abilities. She can cast various spells and she can vanish in plain sight and move almost undetected, or even invisibly. She is able to travel between planes and worlds at will, or teleport short distances within a world.