The '''Theran Empire''' is the main antagonist of the Earthdawn Role-playing game.
It was based on the island of Thera, to the southwest of Barsaive. The empire was considered the chief power at work in the Earthdawn setting, with provinces in modern day Africa, Southern Asia, as well as most of Europe. The Theran Empire, which rose to power during the The Third World (of which little is known), was extremely magically advanced, possessing vast libraries of magical lore, powerful (if corrupt) wizards, and literal 'floating fortresses' ripped from the earth itself.
Theran wizards and politicians warned many of the outlying nations around Thera of the coming of the Scourge and the Horrors, offering the technology and protection of the kaers (underground, warded cities) to those who would pledge their loyalty to the Empire. Most of these nations agreed at first though some became unwilling to fulfill their end of the bargain after the end of the Scourge, wanting to have nothing to do with the bureaucratic nation run on political conflict and powered by slavery.
The Theran Empire survived Scourge. It's effort to retake control of Barsaive form the setting of the Earthdawn universe.
In addition the island of Thera, the Empire controls following provinces
In Shadowrun universe (The Sixth World), there is no public awareness of Thera's existence. It is likely that some individuals (immortal elves, dragons) know about it and even remember it, some perhaps even trying to rebuild it in some form. For general public, the legends of an ancient powerful island, Atlantis, are as close as they get.