Nexus. The Homeworld. The Capital. The City of Gates.
Nexus, known as Ardania prior to the Mage War, is the homeworld and capital planet of all of the Imperium. It is where Emperor Karr maintains permenant residence and is the beating heat of trade, learning and culture for all citizens of the Imperium.
Nexus is a wealthy, populous planet covered almost entire in sprawling cities. Small artisan farms and nature preserves still exist, but most heavy agriculture and industry have moved off planet. Its primary function is trade by control of the Portals. By decree of the Emperor, all Portals connect though Nexus and no other planets. This keeps the Imperium culture centralized and strong.