We all know that nothing in the world comes without a price. Maybe that's why the power fantasies where protagonists get incredible cheats for basically nothing are so popular. But that's not what this sadis-, evi-, awesome hamster is looking for. I am looking for novels where cheats come to protagonists for no price at first... But then take triple payment. Example 1: mc gets cheat system that lets them modify their body and get stronger. After a while the system leaves mc, having collected all the work put in by the protagonist and then some. Example 2: mc gets blessing of God and becomes super op in isekai. Then the whole world goes crazy - sacrifices, sacrilegious rituals and mad decadence all around. Why? Because the so-called "God" was a malicious demon who, through mc's use of power, spread its influence into the mortal world. Obviously, mc also loses power.
+1 I was digging into the theme though, in one CN (and then the bloody author keeps the same shit for his remaining works ffs) where MC trains his body with a super powerful technique and ends up getting hijacked by its creator, he did get better though. Negary just had the system summoned MC to another world just to murder him for his lunch money.
I am really not the Demon God's Lackey: Protagonist runs a Bookstore in a semi modern world. Sees the books as just regular books, but all the books are actually forbidden knowledge. That when read, they can make one crazy or just die when the mental power is not strong enough. I Became the Ultimate Boss: When MC sleeps, he wakes up as Cthulhu in a different world. Cthulhu know this and lowkey influences the MC.
I didn't get far enough to see how it turned out for the MC, but the setup for World of Cultivation had him using unorthodox techniques that could potentially mess up his cultivation and also possibly helping an enemy. I assume the protagonists gets overpowered in the end like happens in all these novels, but it seemed like there was a good setup for things to backfire for a while. If its okay to suggest English published novels, John Gwynne's Faithful and Fallen series starts with a cliche chosen one trope, but puts some good twists on it later.
I think I read a oneshot manga like that. Forgot the name, but the plot went like this. Ugly girl gets visited by a magical teddy bear who promises her 3 wishes but they are all choices between two wishes the bear offers her, first choice: everyone in the world becomes as ugly as her or she becomes the most prettiest girl. She chooses to be pretty. Then the next choice: the world ends or she dies. There is no way out, she has to make a choice. She thinks that its gonna be her end either way so she ends up killing one of the girls that bullied her. Before the second wish was fulfilled she was given a choice to make the third wish: that the world would not end, or she'd wake up from this dream. The ending was kinda messed up too but I don't remember. Your post reminded me of that. I wonder if anyone knows the name.
Devourer of Destiny was great while it lasted, too bad the author stopped due to bitchy readers harassing him, still, the three available arcs are amazing, MC is a xianxia assassin who got defeated and captured, he manages to escape in soul form and latches onto a youngster with the intention of stealing his fate To do this MC becomes a spirit grandpa and teaches him stuff until he can reach a new destiny, thus leaving the original destiny power available for harvesting In WoC it didnt get to happen, the enemy spirit was plotting to abandon the MC and maybe steal some benefits on the way out once it recovered enough power, but then the spirit realized he was too damaged and could not operate outside the MC's body, and decided to sincerely help the MC as that was his best bet
Maybe something like Youjo Senki and/or Kuma Kuma Kuma Bear? Spoiler: Youjo Senki MC's originally an atheist, but to activate her power, namely her computation gem, she needs to pray to God(s), which pissed her off Spoiler: Kuma Bear MC's originally a hikikomori, her power came from the Bear Suit, so try to imagine if you're walking in town w/ such outfit
Can be the inverse? A god curse a soul that is about to reincarnate into a world with level system. Because souls reincarnating in another world with memories are entitled to cheats, the absent and worst, the curse, backfire in the god and the guy reincarnate with an obscene amount of mana. The god also make him unable to learn any magic, and a never existing magic know before - death magic - is avaliable to him because of that, as the pre-requisite of this magic is to be unable to use any other type. The novel is: the death magic that doesn’t want a fourth time.