The Villainess Reverses the Hourglass - Chapter 154

Lin Chen transmigrates to the Dragon Ball world and unexpectedly awakens the Strongest selection system.“Defeat Frieza and prevent the destruction of Planet Vegeta. Reward: Legendary Saiyan bloodline.”“Choice 2: Defeat Supreme Kai. Reward: Supreme Kai’s powers..……

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

At the genesis of the world, the ‘Dark God Entropy’ was defeated in the fight between the five other Gods, and was sealed.

“I'll take this child.” Sold to the Wudang Sect's outer martial arts training hall for three silver coins at a young age, Kwak Yeon dreams of mastering supreme martial arts. But can he overcome the needle-sized gateway barely permitted to trainee instructors and rise to become a disciple of the main sect? “A true gentleman cannot stand idle in the face of injustice!” Thus begins Kwak Yeon's unyielding journey through the martial world, following the ruthless principle of “Kill Buddha, Kill Ancestors”—destroying all obstacles in his path!