The Devil is the 15th of the 22 major Arcana in a tarot deck. He first appears in Nadia's route, at the end Book XIV - Temperance, however makes his first full appearance in Book XV - The Devil. The Devil appears as a humanoid goat with red eyes with black sclera. Unlike Lucio's ghostly goat form, the Devil has two pairs of horns instead of two. One pair curls around his head, the other curling upward. He is clothed in a short red drapery, and a longer black and gold drapery.

The form he takes, the goat-headed Devil, is the same as the image on the Devil card of Asra's deck.

In Asra's route, the devil takes Faust, Asra's familiar. He threatens them, saying that if the MC does not go on a walk with him, he will hurt Faust. If the MC says no repeatedly, eventually Asra and Faust will disappear. If they say yes, The Devil traps them in their realm, meaning that the MC can see everyone, but they cannot see her.

A similar thing happens in Julian's route. The Devil disguises himself as The Hanged Man, in order to trick Julian and the MC. If the MC agrees to The Devil's terms, the MC and Julian are both trapped.