I'm at the South China Sea

Humans are born from human beings, monsters are born from monsters. You two are in love, does your mother agree? This is a world of five continents. There have been demons in the Five Continents since ancient times who like to eat people. In order to survive, the descendants gathered in groups and drove them away; the people were wiser, but the monsters were eventually defeated. Most of them retreated to the Southern Barbarians, while a few hid in the Western Wilderness. Since then, no demons have been heard of in the central and eastern states. People are happy forever, living in two places, free and at ease. But what about the demon, will it come back again?