@Thing482 I'm pretty sure that world doesn't have billions of people. Our world had a total human population of well below 500 million in the medieval times. However, our world didn't have demonic beings claiming their portion of the available land, nor monsters that would basically mean isolated farms and villages would be ravaged easily. Sure, in RL isolated villages were harassed by bandits, slavers, and hostile armies, but it's still better than a constant threat of hulking monsters in addition to the aforementioned. In other words, in that world humans should be less numerous than in ours back during the roughly similar era.
Besides, Krebskrum getting revived wouldn't automatically mean the destruction of mankind. She's been awake before. The same with the other demon kings. Alicia is just delusional by thinking all humans would be automatically annihilated if a demon king came back.