The governmental factions ordered all of their forces in the northern side to start defending against the Undead Disaster. The governmental factions were the most powerful factions in China, and even though their forces in each region weren't very strong, they were located in almost every region.
With how many regions there were within China's territory in the Heaven Awaken World, it was a monstrous force when added together. Moreover, within each of the regions, the governmental factions were at least middle-class factions.
With more factions joining the resistance against Great Qin, everyone felt much more at ease and confident. They didn't believe that they wouldn't be able to stand up against Great Qin with so many people.