I like this question.
At the end of the novel, MC realizes the demon he's been up against is not actually a demon at all. She's a very confused angel. The story ends with him
certain that this creature is not a demon. He
knows. (Monkey wrench: the MC starts off sane, but at the end of the novel, he becomes an unreliable narrator.)
While MC thinks this demon is actually a very confused angel, the readers figure out something else. The reader realizes she's actually a human who made a deal with a trickster. Poor girl is trapped in a deal that she can never get out of.
It's very confusing for everyone involved. She's not really evil, but she keep trying to satisfy the deal she made with this trickster. The struggle comes from the fact that the MC wants the exact opposite of what she wants. She's trying to save herself, and the MC is trying to defend his city. She's not really "evil" they just have different wants.
What does your villain think of Trump?