Kujibiki Tokushou: Musou Hāremu ken - Chapter 29

Amidst an ordinary stroll home, Jake is struck on the head by a mysterious object, plunging him into unconsciousness. When he opens his eyes, the world has transformed. Now, reborn into a newborn in a magical realm, Jake grapples with the surreal fusion of past and present. Navigating the challenges of infancy, he discovers latent magical abilities tied to this extraordinary reincarnation. As the threads of his former life intertwine with his newfound existence, Jake must unravel the mysteries of his past to fulfill a destiny that spans realms and confront the enchanting and perilous journey that awaits him.

Qin Tian accidentally transmigrated into a sickly body, a body with broken Dantian that was unable to practice Qigong, in another world. Fortunately, God had mercy on him by giving him a level up system. Useless? That was him in the past. Not worrying about practicing Qigong, he was now able to kill Monsters to level up. Easy! Level up when killing Monsters; level up when killing people. An unbeatable sovereign of the clan in the eyes of other people, but in his eyes, he is a glittering big BOSS.

Transform into Divine Dragon and dominate the world!
He is the only Divine Dragon in the sea who founded an underwater Dragon Palace.
With Crawfish Soldiers and Crab Generals as his followers, wild sharks and gigantic octopuses as his subordinates, he is the dragon that rules the city.

- Description from Novelupdates

This is the story of a man who had no choice but to become a villain.But not just any villain because even villains have standards.This is the journey of a man learning how to become one. And to help him, the MC has access to an unlimited number of villains in his System Space, pulled from across all realities from every known dimension: Murim, Cultivation, Supernatural, Urban, Martial Arts, Mecha, and beyond.So what is it that Razeal can learn?What can he teach? And why?How can someone with knowledge from nearly every kind of reality reshape the one he’s living in?Someone with the potential to access everything the multiverse has to offer?Tired of seeing the same ideas repeated?The same system copy-pasted with no soul?No real character building no personalities, no free will?Come read this.Who knows you might find something worthwhile.