"Let's Destroy Atherton's Domain" 

The kingdom was indeed still barren, with no houses or other infrastructures, but there were many natural landscapes, such as the mountain for the castle, hill,  caves, and so on. 

Such a place was actually suitable for the blood clan members who could transform into bats when they wanted to. 

Atherton's domain not only had a piece of territory that was large enough to house close to a million pure-blooded blood clan members but also had a sea, a sky, and a moon. 

The sea was full of unknown monsters and beasts that were already there the moment Atherton opened his domain. 

The other land or sky monsters that existed were indeed added by another king from the previous generation from his domain, but this means both people already have natural lives in their domains. 

And the monsters in Atherton's domains all had higher strength and intelligence than the added monsters and beasts from the other king.