In human history, there have been three times of cleansing and the end of the world.
First recorded by Christians, the Great Flood. The Bible Genesis records, "After seven days people and every living creature had gone in, the flood flooded the earth. All the springs of the great deep burst open, and the windows of heaven were opened. The waters were so great on the earth that all the mountains under the sky were covered."
The second time was recorded by □□teacher □□, thunder and fire from heaven and earth. The fifth of the five basic tenets of the □□ religion is "Belief in the Hereafter" - "I believe that everyone has to experience this life and the hereafter. One day, all life in the world will stop and a total reckoning will be carried out, that is, the end of the world. At that time, all people will be resurrected and accept the judgment of Allah. Those who do good will go to heaven, and those who do evil will go to hell."
The third time, spread by unknown ancient books, mankind suffered. It records the legend of two heroes, the blond prince and his black-haired and dark-eyed knight. They accepted the oracle, made a covenant, re-established the order of the new world, and made the new world peaceful and stable for a time. Therefore, the world before the third cleansing is relatively called the ancient world.
An article in the "New Territory Covenant" of the order established after the third purge is, "Everything they have in excess, I will take back; whatever they lack, I will give." The first half of the sentence specifically refers to all the magic families who were pretentious and violated the rules during the three purges. Most of them were deprived of their abilities and disappeared from everyone. Even if ancient magic books are preserved, they cannot be used in the same way as their ancestors, and they can only be reduced to empty shelves and tricks.
The magical families that survived the third cleansing from ancient times are called ancient species. In contrast, the humans who are reborn in the new world are called modern species.
Post-apocalyptic setting