Likely pretty horrifically considering the sheer number of battleships and super capitals in Grábakr, let alone the stronger Shadow in the Warp, Genestealers for basic infantry and mass use of pysker powers.
Outside of trying to throw Titan Legions, massed guardsmen(to slow the Nids for Artillery/ordenatus), deploying dozens of Astartes Chapters and as many Sisters of Battle/Silence units that they could draw on, there isn't much they could do on the ground outside of launching cyclonic torpedoes at every world in its way until they could amass sufficient numbers.
In space the situation might be worse considering how the Trust's ships match up with the Nids; the Imperium would need significant numbers to counter Grábakr in the void. Which ties into the hive fleet's massive number of battleships that the IOM would need to figure out how to face(only saving grace for the IOM is their FTL advantage for redeployment.). Then there's Grábakr's stronger Shadow of the Warp which is another nightmare for the IOM considering that when engaging under it; you have to win and wipe out the Nids or die, there's no retreat.
Last edited:
R: Yes, the old Imperium could have stopped Grabakr, but there's a good chance it would have been pushed over the brink while doing so. And the old imperium could have failed to stop the incursion in time, leading to a massively snowballing Hive Fleet nobody could stop, or the Necrons going all out inside the galaxy.
