This world is divided into four spaces, the heaven, the demon world, the demon world, and the spirit world. Everyone here can practice.
However, these four spaces will be destroyed once every million years. There must be strong power to maintain these four spaces so that they will not be destroyed. This powerful power needs to be exchanged for the Life Stone, and the condition for this exchange is to find the four best weapons in the four spaces.
Intention: acquaintance, knowing each other, staying together