Forbidden Curse: Rise of the Godslayer

Aiden Yale is put into a world where everyone takes a class and works it up. He never awakens one, and that is what he is known for, until a system attaches itself to him that turns ordinary spells into forbidden curses on a world-ending scale. After that he clears dungeons on his own. At the world tournament for young fighters he beats the entries from the other countries. He pushes back the blights coming out of the Void, drops meteors on the field and closes the Heaven and Earth Chessboard over what is left of it. By then the dungeon bosses and the gods in that world take their orders from him.