This novel was called " My Time Is Going Back ". In this novel, the male protagonist would randomly go back in time every Saturday. However, when he met the female protagonist Qin Wan, because of her catchphrase," I hope I can sleep until the end of the world," the male protagonist would wake up and go back to the time before the apocalypse, working together with the female protagonist to save the world. However, there was no mention of the male protagonist slowly making everyone retreat in this novel. I hope this answer can help you.😋I still recommend you to read this novel, because its plot design is very interesting!