I Am Making up Myths in Mixed Martial Arts

The protagonist travels to a seemingly ordinary world of low-level mixed martial arts, but discovers that he has an extremely special golden finger - he can consume "legendary" and "edit" the settings in the martial arts story to come true in this world. As a result, he became the mastermind behind the scenes and spent hundreds of years "upgrading" the world of low martial arts step by step into a world of high martial arts, high magic, and even mythology. The rumors I made up became historical truth three hundred years later.