Ascension

Near the end of the second era the dragons voiced their anger with the prominence of the humanoid races. They understood themselves as direct ancestors of Giapu and claimed ownership of the world. They threatened a great apocalypse if the humanoids didn't give up their empires. All the mighty mages of the 4 schools united and cast a massive ritual. That ritual lifted the mayor cities up into a demiplane over the overworld. The apocalypse didn't came leading to a mistrust against the dragons and the empires being rebuilt.