Internet Magic in Fairy Tail - Chapter 235 - : Teaming Up!

He died on the wedding of the girl he had a crush on, after a long and successful career. After convincing Yama to send him back to the world, he decides to fix the areas in which his life went wrong. Realizing the lack of love and romance in his past life, he sets out to conquer the hearts of various women.

- Description from Novelupdates

Waking up from a hangover, Wang Hao finds himself reborn in an alternate world. To his delight, he realizes that he has a system to help him in this new world. However, his system turns out to be a highly unconventional one. Instead of serving justice and winning the respect of other people, Wang Hao has to do all kinds of bad things in order to make use of the system. So, Wang Hao embarks on the journey to being cursed for good…

In a post-apocalyptic fantasy world layered into multiple realms, humanity faces extinction due to their endangerment of the main realm. Forced to merge all realms back into one, a deity grants humans a leveling system to empower them, lest they become extinct when facing the mythical creatures. Noah, our protagonist, embraces the role of a monster tamer, trading his humanity for strength and eventually transforming into a monster himself. As Noah struggles with his evolving identity, he must navigate a world where the line between human and monster becomes increasingly blurred.

This is a story about Gong Lixin who was the young master of an ancient underground palace in the ancient times. He was raised by his master and forced to partake sexual relationships with numerous people to cultivate his Yin Body. His master who has a Yang Body was going to absorb him after he has reach a level to become stronger. MC refused and killed his master also dying at the same time. Then he transmigrated to the modern time and thinking he will enjoy peaceful life, the end of the world arrived.