There are many unknown forces (controlled by AI) entrenching outside the protection zone, who scatter in the wild in the form of lone wolves, squads and strongholds, etc. They have corresponding organizations, and even countries. They can be challenged. If the challengers fail, these forces will gain experience to level up, become stronger and put the challengers’ gear and items into their warehouse. If the challengers win, challengers can get the gear and items in their warehouse.