Storytellers say that in this world, human beings and monsters are from different realms. Once upon a time, all the monsters were trapped in a place where mountains rose up, all kinds of monsters were born, and the scenery was wonderful. Only children can enter, and only good demons can exit.
Someone asked below, "What about now?"
"Now there are hundreds of monsters all over the world."
"Why not seal it? There are so many weird things in the world..."
"The river that prevented hundreds of demons from entering the human world has dried up."
There was a sigh of relief underneath.
"It's my fault, old man, for telling us nonsense again."
The storyteller smiled but said nothing.