I’m pretty sure there are inaccessible places that will be a spot for a new boss. Like the blocked stairs in South Sands Desert (I think boss here will be the Sphynx or Manticore not sure what’s the name of it but it’s in the costumes), Wolf Cave, and dunno bout the Felshire Castle but it’s a pretty big spot for a boss fight it will be awesome to have a boss lurking there!
Maybe there must be conditions for the boss to spawn not like the other two sk and sm now, example 100 penguin killed for a penguin king xD that would be a special hard work to do