User blog comment:Darknessabove/Huntsman: Echos and Whispers/@comment-25720867-20150602131242/@comment-98.30.55.33-20150605034414

The world isn't necessarily doomed. They did state that once the demon lord get's enough power, she can override the universal laws making monsters only give birth to more monsters. She already partially did this, which is the reason humans and monsters can have kids together in the first place. She just needs more power, is all.