Fortress Cities of Thraen

The plane of Thraen faced a cataclysm hundreds of years prior when the unthinkable happened, a swarm of Tarrasques appeared out of nowhere and threw the world into chaos. The Tarrasques ravaged the world nearly destroying all of civilization.   The civilizations of the world saved themselves from destruction by building moving Fortress Cities to escape the threat of the Tarrasques when they appeared. These Fortress Cities are the only reason any race is still capable of surviving in this crazy world. Magitech was used to create the Fortress Cities but now little is known about this magitech because most who created this magitech kept little records of it or that almost all of the creators were on one Fortress City known as Zalem that no other Fortress City has encountered.   With little knowledge of how to build the magitech used to create the Fortress Cities, there are now smaller Orbital Towns that dwell around most Fortress Cities for protection and offer certain services to the Fortress Cities like mining, production, food, or scavenging.