Cadian Pylon

The Cadian Pylons are a large number of massive pylon-shaped devices of unknown xenos origin erected millions of years ago in a network stretching across the surface of Cadia and a number of other worlds close to the Eye of Terror Warp rift in the Segmentum Obscura. It is now believed by the Imperium of Man and the Eldar that the pylons were erected over 65 million years ago by the Necrons during their ancient war with the Old Ones to serve as a defence against the psychic abilities of the Warp which are the Necrons' only real vulnerability. The pylons act as anti-psychic field emitters, restricting the activity of the Immaterium in proximity to them. The Tech-priests of the Imperium's Adeptus Mechanicus have hypothesised that it is the activity of the pylons on Cadia and the other worlds near the Eye of Terror that are responsible for creating the unusual zone of space-time stability known as the Cadian Gate that is the only known navigable route out of the Eye of Terror into realspace.