MTL - General: Traveling Frog, Starting Blood and Following the Limit - Chapter 4

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.

Spend life energy to infuse martial arts, and you can perform unlimited deductions.

Shen Yi’s mortal body only has a lifespan of less than a hundred years. Fortunately, he can gain his remaining lifespan by killing demons.

In the troubled times where evil spirits are everywhere, the long sword is revealed, causing the liver and gallbladder of these creatures who have lived for thousands of years to burst!

From [Eagle Claw Technique] to [Eight Desolations Splitting Heavenly Hands], from [Demon Subduing Fist] to [Golden Body Prison Suppressing Dharma Appearance]!

Shen Yi occasionally ponders, how come this lifespan is getting longer with more use?

He put the sword into its sheath, raised his eyes to the sky, and heard that there was a Jade Palace above the clouds. It was filled with thousands of saints, each of whom had experienced endless years.

This time I came to heaven just to borrow a million years from the immortals to prove my path to immortality.

- Description from novelbuddy

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