Future Earth

10 000 years ago, the planet was tainted by the invention of magic weapons. Someone opened a gateway to the plane of magic, and the result covered the planet in deadly magic radiation. Humanity were forced underground, while the animals left on the surface were free to evolve and mutate into terrifying monsters. And now, 10 000 years later, the split and drastically evolved humanity can't go back up because of the terrors roaming the land. But as of late, a few people are willing to try...