Atocitera

At a time long ago, a destructive object fell from the stars and through Cataclysm changed the continent of Atocitera. Mountains, containing raw metal which defies gravity when in presence of magical Flow. Subjected to the forceful arrival of Corruption the Flow cut several mountains and lifted them on The Upper Streams.
These mountains became known as Atocites, the only places on Atocitera safe from the influence of Corruption.    As the Corruption stormed the continent, things started changing. Animals and beasts started showing mutations with every new generation, becoming more dangerous with each iteration.
Not even humans were safe. At first contact the Corruption takes something from everyone, giving them their Corrupted limit. Everyone could then either live with new weakness or trade their humanity piece by piece to temporarily get what they lost back.   Humans quickly realized the continent became too dangerous for them and that they had no chance of survival. By undergoing The Grand migration they moved onto the Atocites hoping for safety. The Ground Below, as referred to by people living on Atocites, became so dangerous, that everything down it is deadly and life threatening.   Even though the people of Atocites managed to learn how to survive in the harsh new conditions. The scarcity of resources available at the Atocites makes the people periodically Raid The Ground Below for whatever they need for survival.