Mo Mietian had already arrived at the Domain Lord's Great Hall in Myriad Demons Country. In fact, every Divine Kingdom among the Six Great Divine Nations had powerful spatial barriers. Only envoys of the Heavenly Patroller and Domain Lords of allied nations could freely enter and leave. This meant that even the six Domain Lords could not enter other Divine Kingdoms without the consent of their counterparts.
As for Myriad Demons Country and Annihilation Demon Nation, they were allied; hence, both Domain Lords could freely enter each other's Divine Kingdom. Of course, this was because both Domain Lords had modified their own kingdom's barriers. Similarly, Netherworld World was interconnected with Genesis Divine Nation, allowing free movement for their Domain Lords. Myriad Gods Hall and Myriad Spirits Realm were the same in this regard.
