Maybe a Fake Gintama - Chapter 18: A Certain Author: Respect the Cp Fans of the Original Work! (End of Kagura Appearance~)

The idiot Long Gen pretends to be a pig and eats a tiger, takes advantage of the girls in the village, travels across the countryside and forests, monopolizes the beauty and coquettishness, and achieves the legend of “Dragon Gen”. There is a widow in front of the door leaning on the door to watch, and a sister-in-law next door looking through the screen window… This book is determined to be a stallion, with the goal of pushing down and being pushed.

- Description from novelbuddy

Demons in Academy of Light are described as vile, dark, cruel, evil, impure, and a whole lot of other things. At least, that’s how they’re portrayed in the game—a sacred land where demons and dark energies aren’t supposed to exist. That’s how it was supposed to be... So what the hell am I supposed to do now? Thanks to my rotten luck, my soul ended up possessing the lowest-ranking demon, the one who dies at the very beginning of the story... I’m screwed! I have no other options left... If I want to survive, I have to kill the protagonist.

Mo Chou is the no.1 ranking female assassin in an illusive organization. One day on the way to the organization after completing a mission, she dies. She is shocked when reincarnates into her favorite novel but as a villainess who is the protagonist's step sister and dies a miserable death. She just wants to live a cushy and comfortable life so she decides to completely avoid the red flags aka the main characters and live like a saint (well a saint who is an assassin) But why does she keep stumbling into the main characters especially that infuriating villain and why the heck are they clinging onto her?

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.