Prosper's Demon is a 2019 novella by K.J. Parker (AKA Tom Holt) following an unscrupulous exorcist in an alternate-history (in a time-period reminiscent of the Renaissance era) as he contends with the world famous artistic genius, Prosper of Schanz, and the demon inside of Prosper who is secretly guiding his art.
Provides examples of:
- Cooperation Gambit: The narrator's eventual method of dealing with She and Prosper. The narrator knows that he can't stop Her without killing Prosper, which will in turn result in the narrator's execution at the hands of the Duke. The narrator also knows that whatever plan She is doing, it is so long-term in scale as to be completely incomprehensible to a mortal human, and so any negative effects won't be felt until long after his death. So he decides to help with the horse project. It seems.
- Divinely Appearing Demons: The narrator laments how She, the demon from another territory, is apparently insanely attractive while the demons in his own locale look like disgusting shellfish creatures.
- The Dreaded: The narrator, as a particularly harsh exorcist, is known and feared by many demons. It's to the point that some of the demons he encounters agree to leave their hosts without a fight, simply because they know the narrator's reputation and don't want to risk his ire.
- Harmless Villain: how the demon, "He" is portrayed for much of the story. He is whiny and ineffective, and each time the narrator runs across him, he begs the narrator to leave Him be so He can rest, sounding like a sleepy child who doesn't want to go to school.
- The Narrator: Out.Him: I just got here.The Narrator: Tough.Him: Five minutes, all right? Just give me five minutes and then I’ll be on my way.
- Historical Fantasy: The world looks a lot like the Renaissance period, but it is common knowledge that there are demons running around and exorcists to stop them.
- Knight Templar: The narrator. By his own acknowledgement, he doesn't have scruples when it comes to exorcising demons, even if it means killing their helpless human hosts. In order to get to the demon Her, he buys a little girl, allows her to be possessed by a demon, and strong arms the demon into working for Prosper's project. He also murders the entire royal family, as well as a number of innocent bystanders, all in order to thwart the demons' plans.
- The Legions of Hell: According to some scholars the narrator has studied (though doesn't think highly of), there are 72,936 demons on Earth. They cannot die, but they can be harmed and thrown out of their hosts, and at least some of them are working towards a long-term goal at the direction of a Lower Power.
- Level Scaling: In a rare, non-videogame version of the trope, the narrator and Him have a strange connection that even the narrator cannot explain; though the demon is unquestionably thousands upon thousands of years old, as the narrator has grown up since their first meeting, so too has He. When the narrator is a child, the demon speaks and acts like a child. When the narrator is an educated adult, the demon seems to have become more clever, and starts using academic language, as though He is learning along with the narrator.
- Mercy Kill: The narrator is no stranger to this. His church order even has this as a lesson for exorcists; eventually they will come across a situation where they have to weigh the evil of letting a demon stay inside an innocent in the hopes of convincing it to leave peacefully later, or ending the suffering immediately at the cost of the host's life. This is also why the narrator hates the demon Him so much: He possessed the narrator's three month old niece in the hopes of dissuading the narrator from exorcising him again. It didn't work.
- Mirroring Factions: it's specifically mentioned by the narrator that most exorcists and most demons really aren't that different from one another. In a more specific sense, he feels that he and Him are very much alike, to the point where the narrator figures out where He is hiding and why by simply wondering where he would go if the situations were reversed.
- No Name Given: The narrator is never named. The demons, also, are not named, though that is intentional on the part of the narrator, as the church warns exorcists not to get too familiar with the demons. The fact that the narrator even refers to the demons and He and She is an overstep.
- Our Demons Are Different: The demons in this world are immortal and can possess human beings, but they have no true form of their own, and are easily overpowered by human exorcists, even ones who are small children. It is specifically said that this power imbalance is the trade off: demons are eternal, but weak. Humans are mortal, but have substantial power over them.
- Pay Evil unto Evil: The narrator's perspective in regards to the demons he deals with.
- Van Helsing Hate Crimes: While all exorcists target demons, most do it out of a desire to help others. The narrator, on the other hand, is more driven by his desire to hurt demons, and is specifically known for being much harsher in his exorcisms than neccessary, even if it costs the innocent human hosts' their lives.
- Well-Intentioned Extremist: The narrator admits that, while saving people is all well and good, he is definitely more driven by his desire to hurt demons than he is to help his fellow man.
- Would Hurt a Child: Demons and exorcists alike. Pulling a demon forcibly out of anyone is likely to leave the host damaged, either mentally, physically, or spiritually. Adults have a better chance of surviving intact than kids. Demons hope that most exorcists would hesitate to harm a child, and so kids (especially unborn babies) are easy targets. However, exorcists are taught that it is better to Mercy Kill a host that cannot be saved, rather than let their minds/souls be trapped with, and fed upon, by a demon.
- Part of the narrator's backstory is that when he himself was a child, he conducted his first exorcism on one of his schoolyard frenemies who was being possessed by the demon Him. It didn't end well. This was also the fate of the narrator's young niece.
- Xanatos Gambit: How the narrator kills the entire royal family, ruining whatever plans She had in mind. He tricked the demons into thinking he was cooperating with them, helped Prosper build his giant horse statue, then filled that statue with explosives that would ignite at the unveiling ceremony, where the entire royal family (and the demons possessing them) would be.
