The Inheritance of the Human Race Is Cut Off, How Did You Become the Emperor?

In this world, the human world has been invaded by demons, human knowledge has been cut off, and human civilization has been destroyed. The human race that lost everything was fed by demons, and at the end of their lives they became the demons' food. Riche traveled to this desperate world. In three days, you will face being slaughtered or becoming the pet of a demon. Fortunately, Riche gained the magical ability to project himself into past history. During these three days, he continued to deduce history. Learn the abilities that countless human races have spread throughout the world. It changed the outcome of human civilization being cut off time after time. So, when the demons opened the breeding farm in the underground cave and prepared to drag the humans inside to slaughter, they were suddenly horrified as to how the humans who had been slaughtered by them had become so powerful!