Beginning with the Ubume Bird - Chapter 1 - The End of the Big Gun

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Ed was transported into a world of Hunters, a harsh and extreme environment.In this world, winter days last only two hours, and even in summer, the daylight barely stretches to six hours!What makes it even more eerie is that when night falls, all creatures of various races turn into violent, frenzied monsters. Evil spreads everywhere, and the night itself becomes humanity's worst nightmare!Hunters, however, can only train through the Sunlight Meditation Technique, using the brief daylight hours to cultivate their strength.But Ed awakens the Moonlight Meditation Technique!From that point on, while others flee from the night, Ed thrives in it, growing stronger and stronger with each passing day!He slays dark sorcerers, exterminates vampires, and defeats the Wolf King!Gradually, Ed becomes the strongest human to ever exist!

Su Leyun, the legitimate daughter of the Hou family, was replaced by a peasant woman during a plague when she was still in her infancy.

After experiencing hardships in life for more than ten years, she finally returned to her parents, but she was plotted and framed at every turn. She was even looked down upon and treated coldly because she grew up in the countryside.

She originally thought that her sincerity would impress her husband and win him the gift of betrothal, but she didn’t know that he only married her for the sake of pretending to be a match.

After resurrecting her life, she vowed to make those who bullied her pay the price. She knew what it meant to be respected as a legitimate daughter!

- Description from novelbuddy

Okay, so let me get this straight. I wake up and BAM, I'm inside the body of Valerian Thorne—a third-rate villain. I mean, come on? Out of all the characters I might have been reincarnated as, it had to be him? This man was literally a stepping stone for the actual hero. So why him? Why not someone with a little more. potential?Now that I have a system that can unleash Valerian's hidden potential, who knows? Perhaps this third-rate villain will get a second chance, alter his destiny, and prove the world what he is truly capable of. And if I happen to get to keep the gorgeous fiancée in the process. well, I'm not complaining.