Aionos

Aionos is a moon of the gas giant Kylasma, lying near but not within the Statheros System. No segmentum or coordinates for it are recorded. The moon was covered with the wreckage of civilian ships and with ancient xenos pyramids, implied but not confirmed to be of Necron origin.

In the Battle of Aionos, Commissar Sebastian Yarrick and the 252nd Steel Legion fought the Heretic Astartes warband Harkanor’s Reavers on the moon, approximately a hundred years before the Second War for Armageddon, in a year not otherwise recorded. As his force withdrew, the xenos within the pyramids were recorded as having stirred; he is not recorded as having fought them.