Xenos activity on Corticant increases

The Hammers of the Emperor, by failing to deal the eldar on Corticant a quick and crushing victory, had instead awoken the eldar to an emergent threat to their control over events in the Aleph Sector. The imperium could not be allowed to take the device on Corticant which was the key to the strategic situation in this part of the galaxy. While the human empire may be needed in the final showdown against chaos, the Kel Sandros craftworld and its allies resolved to make sure it was the Aeldari race that would steer the path to final victory. 

The eldar knew the elite Grey Knights could not be everywhere at once, so began a two pronged assault via the tactically important valleys which controlled access to imperial held territory. 

Along the Iron road in the east, the eldar met little resistance, until their scouts reported “irregular human forces” ahead of them. Suspecting something was amiss, the eldar deployed a full strength war host to the eastern sector, finding to their dismay that the “army” standing in their way was not imperial at all. Yelling and whooping while riding around on buggies and bikes the Cult of the wheeled emperor - part of the growing genestealer infestation of the sector, had obviously decided that the time for their uprising was at hand. 

Realising that Tyranid control of the necron device posed an even greater threat, the war host was diverted to crush the irregular army careening in front of the Aeldari wraithhost, but the fight itself proved difficult. The speed and unpredictable fighting style of the enemy was totally at odds with the millennia old martial doctrine of the eldar, and they soon found themselves in the midst of an ambush. However, the wraith guard, supported by a towering wraithknight, proved difficult for the light forces of the genestealer cult to deal with, and despite taking heavy casualties the cultists were gradually worn down, then broken, allowing the eldar to secure the vital territory around the Iron Road. 

In the west however, imperial scouts detected the eldar advance, and the Grey Knights swiftly deployed to counter the alien advance. After a brutal battle south of Lochford the eldar were forced to withdraw, although the strategic position on Corticant still hung in the balance, and  General Veers, commander of the Perseus Deeps, urged Lord Commander Maximus to divert more forces to Corticant before his garrison was overwhelmed.