Game Of Life System! - Chapter 8: Buying a watch at the speed of light

Brutality is my style of conduct! If you can't accept that, I'm ready to fight—that's who I am!Don't mess with me, otherwise, I won't mind teaching you the meaning of “The Return of the King”!!!

After ten thousand years of cultivation, he could have achieved immortality. However, his lack of human experience led to his failure to attain immortality.Thus, he resolved to immerse himself in a century of human existence, seeking to enhance his journey toward immortality. What he didn’t anticipate, though, was that upon entering the human world, he would find himself cast as a son-in-law, facing disdain not only from his wife’s parents but also from his beautiful wife herself.Armed with a wealth of cultivation knowledge, how could he transform his drab human life?

Outer Sect Disciple Chen Yu, assimilates within his body a fiendgod heart.

The heart, is the backbone of life, the human body’s fatal vital point. And it can be said that Chen Yu’s heart is actually his strongest defense point, and permits him to overtake demonic beasts, or divine beasts unlimited potential.

Henceforth, he steps onto the stage and surges forth on a magnificent scale, in a heart-rending mysterious journey.

Talented as a cloud, an unparalleled supreme talent.

10,000 races glorious, cross boundary battles.

Only my heart, eternal!

- Description from Novelupdates

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!