iron pyramids

Ancient (~7Gy?????) alien structures made of iron compounds that weren't previously encountered anywhere.

They were discovered because the particular pattern of interference caused to sensors of the Explorer Drones. After analyzing the disturbances, crewed ships were sent to investigate. 

Zero Nomads, before their departure, had reportedly used their measuring devices on one of the Pyramid (which one?). They claimed that it beams a stream of energry through Nullspace. Years later, the Iyoa Vo was located by an unknown party by looking for the Nullspace-related disruptions.

There may be a connection between the Fallen Ones and the Pyramids. The Prophets started to regularly mention the demonic entities after the AFTERTHEPYRAMIDWAS touched by a human being:

'They Made The Pyramids As Conduits To Amass More And More Power But The Price Of Creating Them Was So High That The Entire Kingdom Collapsed The Entire Civilization Fell From Grace And Become Cut Off From The Core Banished Forever'

- The Blasphemous Prophet

There are five known Iron Pyramids*:

1. Orbiting the Norn Star on highly elliptical orbit (86-232 AU);
2. Near Kralmor's south pole;
3. Buried under the surface of Iyoa Vo;
4. Detected inside the Nehariel Nebula;
5. *) there are many reports about the Iron Pyramid present somewhere on Hephaestus but it wasn't directly located.

6(?) -> Pyramid in the Black Plains? Report of a Dying Explorer states he saw one, somewhere 'inside' the anomaly.