Supreme Casanova: Ultimate Harem System - Chapter 210 Totally Worth It.

Perhaps it is the choice of fate. As a senior otaku, Qian Lingfeng got the “steel shell system”. However, when he swept the world with the system, became a local rich man, made all kinds of beautiful women, opened a harem, and realized the ultimate fantasy of thousands of otaku, he found that things seemed far from simple!
When the end comes, biochemical zombies suddenly come down, fierce beasts are in power, bloodthirsty zerg roam to kill the world, and human lives are comparable to dirt. Where will weak human beings go in this world? Is humanity going to be extinct? Or … can an otaku save the fate of the human race?

- Description from Novelupdates

Xin Xiu exclaimed, “Master is a panda!”

A young Brave walked out of his village, gathered companions to his side, defeated the Great Demon King, became famous, then came back with beauties in hand! This was a legend that appears in the world of Seyrol every 200 years!

Our protagonist, however, isn’t a Brave. Even so, for over a thousand years his figure has loomed throughout its history.

Unwittingly, the name of the Red-robed Priest began to resound throughout the world. Red-robed Priest’s legend included extraordinary sword techniques and magic, erudite knowledge, and an almost prophetic ability to lead young Braves toward the proper path. People of the world think of him as a descendent of the ancient Yellow Race which led to his omnipotence. In essence, however, this was just the characteristics of the profession known as ‘Noble’.

- Description from Novelupdates

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.