If one monster could change and upturn the fate of one realm, how much more could others? When a Colossal Beast awoken deep from its sleep, its brethren—minions, underlings, family—would also be roused. From their own caverns, much smaller than the Colossal Winged Wyvern's but still larger than any city were the sounds of squawking and screeching as thousands of wyvern flew out of their own caves.
For if the biggest monster would be marching out of its territory, then there must be some greener, or rather better place for them.
And so they flew out from the Endless Passes, shaking the entire army and groups of people that camped around its border. And unlike the Colossal Beast with its destination in mind, the others were much more willing to frolic around and snatch up some tasty snacks while they followed after their 'big boss'.
It spelled mayhem and bloodshed across the camp.