Steel Shell System

Qian Lingfeng, an avid Otaku, received the “Steel Shell System” by the choice of fate.
After he conquered the world, became a rich tyrant, met all kinds of beautiful women and opened a harem, and achieved the ultimate fantasy of thousands of Otakus, he suddenly realized that things seemed far from simple!
…
The end befell onto the world and zombies suddenly started appearing. Fierce beasts are now in power, bloodthirsty Zergs now roam and dominate the earth, and human lives are now reduced to dirt.
Where will the weak humans go in this world? Is there even a place left for them to get a foothold? Is humanity going to be extinct?
Or… can an Otaku save the fate of the human race?