The mysterious pylons of Cadia have stood since long before the coming of Man to this remote world. But their ultimate purpose remains a mystery. It is currently believed by the savants of the Imperium of Man and the Eldar Craftworlds that the pylons were erected over 65 million standard 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 essentially 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 the pylons on Cadia exert some effect over the Immaterium, rendering it calm and creating the unusual zone of space-temporal stabi