The subjectivity of Mononoke is a large part of what makes the series unique. But, one of the biggest mysteries that the show leaves unanswered is what exactly the Medicine Seller is supposed to be. From his weird powers, traits, and appearance to the fact that he clearly doesn’t age, it’s an understatement to say that this isn’t a normal guy. All kinds of theories have been floating around about the Medicine Seller’s true identity, that he’s a onmyōji, a god, or some kind of benevolent mononoke.
However, for my money, looking at all the evidence combined from the show and Japanese mythology, I’ve concluded that the Medicine Seller is most likely a kitsune.
Now, I feel like most anime viewers have at least a cursory idea what a kitsune is, but just to recap: “Kitsune” (狐) is the Japanese word for fox. Traditional Japanese folk beliefs attributed all sorts of mysterious powers to foxes, including shapeshifting, creating illusions, and warding off evil spirits. Taking cues from ancient Chinese lore about fox spirits, kitsune have captured the imagination of Japanese artists and storytellers for centuries and continue to do so in the present day.
I’m far from the first person to come up with the “Medicine Seller is a fox” theory. It’s the only theory cited on the admittedly bare-bones Mononoke Wiki, and numerous commentators and Tropers have speculated that our favorite flamboyant exorcist might be a fox in disguise. So, allow me to take some time to display all the compiled evidence as to why I think this is the most plausible theory.
