Aura Kingdom System

In an alternate version of our earth, a portal appears in a random location. This portal is connected to a place called Dungeon. This Dungeon is a pocket dimension filled with monsters. When this portal appeared, many humans on earth died, killed by the monster that spawned by the Dungeon. Fifty years later, the earth has changed. Many people use the Dungeon as their job. This is a story about one man that gifted with a unique ability. He did not know that this ability has side effects. Will the man become powerful enough to overcome the side effect? Or will this side effect destroy the world?