Apocalypse: My Underground Fortress

(Apocalypse + reborn + special abilities + shelter + no do-gooder protagonist + evolving zombies + building a faction)

Synopsis:

After scraping by for ten years in the apocalypse, Qin Yu transmigrates back to twelve hours before it begins, bringing his special ability with him. To prevent his parents from dying horribly and his friends from perishing, and to avoid repeating the tragedy of surviving alone, he decides to build a massive underground fortress and wage tunnel warfare against the zombies beneath the surface.

The three rules of the apocalypse: 1. Don’t team up lightly unless you’re stronger than everyone else combined. 2. Stay away from crowds. The more people there are, the more dangerous it gets. Once a gathering exceeds seven people, a zombie horde of some size will be triggered. 3. Send our own do-gooders away, and protect the enemy’s do-gooders.

(Zombies have nine ranks, with Rank One the weakest and Rank Nine the strongest.)