I've got a new book titled 'SSS-Rank Villain System: The Hero is Overpowered'! You can find it on my other profile.
I highly recommend reading it if you like my style of writing. (At least read the Prologue, it's something I spent a decent amount of time on, and I'm sure you'd be surprised what it entails!)
I'll leave the synopsis here.
Without villains, there can be no heroes.
[Testing suitability with subject]
With a powerful hero running through the world, protecting the world from anything and everything, what the world needs now, is a villain who can compete against her. By all measures, her reign was absolute. For years, several underground organisations have been trying to find a way to create something stronger than the hero. Otherwise, they would undoubtedly be wiped out.
The greatest success of the Rudiless Project is a young boy by the title of Subject K. He is the pinnacle of their scientific development, combining with the 'System Agent' to wield the greatest system ever developed.
Despite any wishes the young boy may have had, he would be forced into the role of playing the absolute villain. With no care for his well-being, the system only cares about developing his strength, with the hope of eventually being able to defeat the hero. Missions after mission, he would sacrifice more and more of the world, with the hopes that his one and only wish.
He hoped that one day... he would be able to see the girl he loved... once more.
The only way to do so was to defeat the hero. Thus, the ultimate weapon was created. Kay Rudiless, the most unfortunate boy in the world, would become the greatest villain in the world.
Here's a link: