The Ghost Reaches are technically part of the Rimworlds. They represent a huge swathe of territory ravaged by The Apocalypse. Before The Apocalypse these worlds were a vital part of The Legion Empire. They were filled with countless metropolis and billions of people. Unfortunately they relied heavily on Legion’s Soul Tech. When Areis shunted life destroying etherium through all access points to the ether, each and every one of the Soul Tech batteries became a weapon. The life on these worlds was wiped out in an instant, leaving the super-modern technological artifice within the cities to themselves. Now these cold wastelands are punctuated by ghost cities who’s machines occasionally have come back to life. Few machines had any kind of intelligence, and all of the intelligent machines have been cut off from any communication beyond their own world for a long time. Many explorers who have entered the ghost reaches have met these machines and have never returned due to a paranoid/overzealous machine army controlled by a mad intelligence.