The Empire of Miradorium is also known as the 'Realm of the Land & Air'. It claims the land because the humans now occupy almost all of its land and it claims the air due to the power of the emperor's floating palace known as Songborne.
It however has other realms that technically are autonomous within its boarders. These include the Realm of the Canopy, the Realm of the Underbrine, the Realm of the Undercroft and the Realm of the High Peaks.
The land of the empire is divided into precincts ruled by different High Born Families who all answer to the Emperor.