Asteroid GX-923 was a large, rocky asteroid composed mainly of iron and silicates. Its mass was estimated at thirty billion tonnes.
Towards the end of the Cyberon War, the last Cyberleader oversaw the hollowing-out of the asteroid in secret, and a force of Cyberons went into hibernation inside it alongside a supply of frozen organic prisoners ready to be turned into new Cyberons by the Conversion Engine when it became necessary. In 3245, it was surveyed by human authorities, but they did npt realise its true contents and remained unaware of the Cyberon threat.
It was only in 3909 that the Cyberons awakened, attacking the SS Titania and then moving the Asteroid itself through space to menace Vega Station with its built-in laser superweapon. However, Christian and Emily were able to infiltrate the Cybernet and save the Station, causing critical failures within all the individual Cyberons and leaving the asteroid base essentially dead, its final inhabitant the consciousness of the Cybernet itself, which knew it had no hope of rebuilding the Cyberons. (PROSE: Cybergeddon)