The War of the Imperial Succession

[Mestra]

Looks good to me. This gives the Imperium ample time to prepare for war. Three years is more than enough time to stock pile provisions, build ships and bolster the Imperial Legion (Mestra). It might be possible for smugglers to get around faction navies to get supplies from Mestra to the Imperial Legion, could also be how the Imperium is getting its intelligence from the north.