Demonic Creatures are a common sight on the Western Continent and are known to form armies to invade kingdoms and empires every two to three days. This armies are normally led by commander-level monsters that have intellect on the same level as NPCs.  This is led to numerous NPC kingdoms and empires to raise armies to protect their borders and the remaining NPC Cities to be managed by the Adventurer’s Association.
If any of the kingdoms and empires fail to protect their town and cities, it will be captured by the Demonic Creatures and players' range of activity would be reduced. Due to this fact, the western continent does not have clearly defined neutral maps and the territory each kingdom and empire possesses is in constant flux. 
It is mentioned that constantly fighting against Demonic Creatures helps to improve one's combat standards.