Perhaps due to the existence of Sage Crystal, countless terrifying creatures were born on Earth in that era. Even though humans evolved powerful technology and ancient martial arts, it still didn't change the fact that those creatures were at the top of the food chain.
Later, the people of Earth discovered the presence of the Sage Crystal and its uses, but it was too late, as a group of interstellar explorers had found Earth and discovered an enormous reserve of Sage Crystal.
However, lacking the correct usage methods, those creatures possessed only strength but lacked wisdom. Otherwise, if they had united with the humans of that era, there might have been a chance to drive away these invaders.
Those ancient creatures, even the weaker ones, possessed Source Energy Level combat strength. Creatures as strong as the Orochi even held power not weaker than a Source Energy User or even a Divine-level being.
