Halfway through the cycle begun by XI. Bear, we encounter her nemesis. XV is traditionally the Devil, who, like Monkey, stands for greed, deception, and subjugation.
Like the Fool, Monkey carries a stick over his shoulder, but his holds infernal light. He walks to the West (that is, the Past), showing a reversion to base instincts. On his back he has a picture of Bear in captivity, as a reminder of his selfishness.
Similar to many artistic depictions of the Devil, Monkey “apes” the shape of a human. In the song, his hand as opposed to Bear’s paw is used as a mark of superiority. Where V. Emily is a bridge between terrestrial and celestial, XV is a bridge between human and bestial.
Still, manipulation can have a nonnegative sense – the five fingers of a hand (or a Monkey’s foot) are a marker of developed skill. Questionable motivations aside, Monkey is very clever. Ingenuity can fashion tools, as well as hold leashes.