From Human to Skeleton: Revived with Infinite System Crystals - Chapter 10: A Painful Touch

After the gold medal teacher, Sun Mo of the city’s No. 2 Middle School, fell into the water, he transmigrated to Tang Guo, Zhongzhou Academy and became a newly graduated intern teacher. Sun Mo bound the Peerless Master System, turning waste into little geniuses. Under Sun Mo’s guidance, the little children became masters after one year, passed emperor level after three years, and attempted god level after five years.

The man forsaken by the world, the man a slave to money and the man known as the legendary God of War in the highly popular MMORPG Continent of Magic. With the coming of age, he decides to say goodbye, but the feeble attempt to earn a little something for his time and effort ripples into an effect none could ever have imagined.

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

I got transmigrated into a game I’ve never seen before.

I thought it was a top-notch RPG and spent 30 years on it.

I retired as a war hero and planned to spend my remaining time leisurely.

But it turns out, it was an academy story?