Endless Leveling Done Right! - Chapter 63: The Oathkeeper’s Last Oath [Part 2]

In the continent of Chang’an humans had lived as livestock and slaves to the Primordial Beasts. These beasts were ferocious, bloodthirsty and overwhelmingly powerful, but even so, the humans managed to prevail in the face of despair.

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

A man who races against time in the Marvel universe, hungry for pleasure. In the dark night, Nuohe stood on top of the building in a black robe, overlooking the bustling New York City. He lowered the brim of his hat and said in a low voice: They are restless, because I…

He grasped the supreme mystery, transformed into one identity after another, staged a big show, but in the end all became real

Behind him, there are many people standing, Madara with Sharingan open, Artoria holding the holy sword, Doflamingo laughing, proud Gilgamesh…

- Description from novelbuddy

This story is centered around the man named Yi Ji-Hyuk, who has spent 1000 years in a Medieval Western fantasy-like world before returning back to the modern-day Earth. When he returns, he finds that his home is facing monster threats, and that humans with superpowers have appeared to protect the innocent people of Earth.