Later, He Became A Royal Healer - Chapter 92 - Tooth.

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

Son of a bitch! I just finished this godawful fantasy novel, and now I'm knee-deep in it – as David, the disgraced son of the Solarian Empire's top general! Talk about some twisted cosmic joke. But hold on a damn minute... maybe this isn't all bad. Armed with the knowledge of that trashy plot, I can become the ultimate shadow player, an overlord perhaps. Screw the damsel-in-distress harem too – it's time to pull the strings and become the real power behind the throne. This isekai might be a steaming pile, but I'm rewriting the ending with a little more... Debauchery (wink wink).

I was playing a boring game where you don’t level up no matter what you do, there’s no event happening and it was even FREE on *** store. I had an argument on relationship stuff, was angry and decided to destroy the village in a game, then a notification pop-up…

-Your karma has increased by 10.

-You are now at level 2.

Graphics of the game changed. Acquired magic. Saved a village girl that was chased by bandits. Gained a cultist.

It seems the events are starting to take place. Lets see what happens…

When you get to the other world, you acquire new properties, there is no limit for your achievements and you become an overlord…Welcome to my world…

- Description from Novelupdates