Byrne City served as the primary city and capital of the nation of Demophon. Situated on the landmass of Junno, Byrne City was constructed with a dome in order to shield its inhabitants from the harsh environment of Demophon. A network of subterranean passages linked the city to other significant urban centers on Demophon, providing a route for individuals escaping the planet's inevitable demise to reach Byrneport, the planet's main spaceport.
When the star within the system underwent a supernova event, Byrne City, along with the entire planet of Demophon, met its end.