The upheaval system

On one peaceful evening, something shocking occurred that shocked the entire world's population, the sky began to fracture. Countless creatures begin to emerge from the things known as the Abyss. Mankind battles the monsters with all their might, but the hot weapon proves impotent in the face of this monstrosity, when mankind is at their wit's end. Comes an expert, armed with a cold weapon, and he alone drives the raging beast, gaining a foothold for humanity. From then on, humans continue to improve themselves, in order to live, mankind learns how to manipulate the energy known as Chaos. This is the story of an orphan who attempts to vanquish the Abyss from the earth's surface. Because everything said here is fictional, don't take anything too seriously.