The devil grows by devouring souls. The soul is the food of the devils and the foundation of evolution. If the soul cannot be obtained from other worlds, the devils can only kill each other. The devil world is like a huge seal, unable to actively communicate with any world. This is also the reason why the lords of the great devils continue to fight each other. However, a rare devil, which has no body and life, can possess them through extreme desires and resentment in the foreign world, and let those ignorant live in a way that bewitches people's hearts.