The Starfall

Disaster / Destruction

The apocalypse that destroyed the previous civilization

While the causes of the event are unknown, the Starfall caused nearly all ambient magic to disappear, all of which was then 'invested' into what then became the Wastelands. The Wastelands, corrupted by more magic that any one location should ever contain warped. Anything living or even recently dead was turned into a warped reflection of itself. Nearly everything created that day ran on pure magic and death, true Monsters.
The rest of the continent didn't stand a chance.