The ruins Green had discovered in the territory he had claimed around the Graveyard suggested that the Mist World had once suffered an Undead Calamity of its own.
After the undead erupted on a massive scale, a century of savage warfare followed. In the end, several of the strongest undead lords advanced to Calamity Rank by devouring their own kind.
But the Mist World was already nearing its end and could not sustain beings of Calamity Rank. Those newly ascended undead would have been rejected and suppressed. The Undead Calamity had also consumed nearly all the Death Psychic Energy, leaving them unable to survive for long. They could either leave for the Netherworld, seal themselves away, or be sealed by others. With that, the Undead Calamity would end, and the Void World would slowly pass from its Terminal Stage into recovery. It would regain its strength and nurture its World Origin, completing the cycle.
That was what had happened in the Mist World where the Graveyard stood. The Calamity Rank Skeleton Lord Green had encountered in the ancient tomb had been sealed near the end of the Undead Calamity by the surviving human forces, at a cost almost beyond imagining.
Green had only just noticed the Death Psychic Energy rising in this Void World. He had not yet realized an Undead Calamity was approaching, but that did not stop him from putting it to use.
Once he noticed the change, Green promptly summoned most of the undead creatures from the Graveyard into the Void World. He left only the Death Angel Clone and the Shadow Red Dragon behind for emergencies; all the others came to the Void World he currently occupied.
For now, though, Green wanted no unnecessary conflict with either the Kingdom or the Rebels. Northern Province's frozen landscape