Once you defeat the Bone Mass, the raid variety intensifies: Drakes accompanying a freezing wind, Wolves attempt to hunt you down, An army of Skeletons besiege your base, A swarm of bats will find their way through your bloody rafters!: and of course, the trolls never learn their lesson.

Another Player mentioned building your base in a borderland between biomes, and I can honestly imagine what he has in mind: I've witnessed, and sometimes even provoked full-out wars between the Undead and Fulings! Best time was when the wolves tried hunting me through a Fuling village under attack by Undead - after I accidentally brought a sea serpent in through the swamp lagoon!