MTL - Harry Potter’s Book of Sin - Chapter 2619 that's how it should be

I was betrayed. Slaughtered. Left to die by the people I trusted most — the women who loved me, and the hero I called a brother.But death wasn’t the end.Ten years before it all collapsed, I opened my eyes again. Same world. Same faces. But this time... I had a System.Not just any system — a Sex System bound to my very body. Each conquest fuels my power. Every ring I unlock grants me new skills.They thought I was weak. Disposable. Easy to manipulate.Now, I’ll corrupt them one by one.Not just for revenge... but for pleasure.Reincarnated with a Sex System. Bound by lust. Driven by vengeance.No one gets out untouched.

This novel is also known as Transcendental Mechanic

What do you do when you wake up and find yourself inside the very game that you love?

What do you do when you realize you that you have not only become an NPC – you have even been thrown back in time to before the game even launched!

What will happen when our protagonist’s two realities coincide?

Han Xiao was a professional power leveler before his transmigration. Using his past life’s knowledge, Han Xiao sweeps through the universe as he prepares for the arrival of the players. This is definitely not your typical transmigration novel.

- Description from novelupdates

Sam Sanderson is envied by many for his job, however he himself didn't seem to like it much.

Due to his expertise in nanotechnology he was tasked with monitoring the state the Valkyries, humanity's strongest weapons who all just happen to be made into gorgeous females.

Forbidden from even touching any of them, Sam spends his days in agony watching flowers he couldn't hope to touch. However one day all of that seemed to change.

Fate had never been kind to Ji Ning. Wracked by illnesses and infirm his entire life on Earth, Ji Ning knew early on that he would die as a teenager. What he didn’t know was that there really was such a thing as life after death and that the multiverse was a far larger place than he thought.

A lucky twist of fate meant that Ji Ning was reborn into a world of Immortals and monsters, of Ki Refiners and powerful Fiendgods, a world where Dynasties lasted for millions of years. A world which is both greater… and yet also smaller… than he ever could imagine. He would have the opportunity to join them, and in this life, Ji Ning swore to himself, he would never let himself be weak again! The Era he was born into was a Desolate one, but Ji Ning would make it his era.