At the End of the Day, Hand over the System to the Country at the Beginning

[Rebirth+System+Multiple heroines+Not the Holy Mother] Lin Tian, you don't want others to know that you are a time traveler. The sky was dark and gloomy, and earthy yellow acid rain continued to fall. It's 2076, and the end of the world has arrived. The unknown virus broke out in country M five months ago and quickly swept the world. The infected people who were exposed to the acid rain carrying the contagious virus mutated one after another, like walking zombies, trying to eat their own kind uncontrollably. Lin Tian was reborn and handed over the system to the country The realm is divided into: enhancer, evolver, enhancer, limiter, pioneer, sublimator and immortal.