Editing Conquest of Galaspar (section)

==Prelude==

Mortarion ordered the assault barque ''Fourth Horseman'' to be specially reinforced for ramming tactics and began collecting and outfitting asteroids and decommissioned destroyers to use as fireships. His legion began drilling in the tactics he would use, though none of them yet understood their primarch's purpose. Once he was ready, Mortarion briefed his captains and commanders on his intentions. Their target was Protarkos, the largest hive on the Cluster's capital world, and the Comptrollers who lived there. They would use the fleet as a spearhead to punch cleanly through Galaspar's defences before ramming the ''Fourth Horseman'' into the side of Protarkos and deploying to seize the hive and kill the High Comptrollers before reinforcements from the other hives on the planet could arrive.

When Mortarion led his fleet into the Galaspar system, the Comptrollers fatally underestimated his intentions and capabilities. Assuming that the Death Guard intended to fight a conventional battle, the Comptroller of the Navy deployed the closest groupings of fortress monitors and orbital gun platforms against them, aiming to slow the Death Guard down until the rest of the system's defensive forces could join them. The fortress monitors were met by a wall of engine-equipped asteroids that absorbed their initial salvoes before detonating once they had taken enough damage, destroying many of the orbital platforms and damaging several of the fortress monitors. Now came the second stage of Mortarion's strategy. The decommissioned destroyers, refitted with as many guns as they could carry and loaded with explosives, charged the monitors and detonated as soon as they were close enough, destroying most of the enormous vessels. In this way, the Death Guard easily breached Galaspar's first line of defense in exchange for several escorts and capital ships. Mortarion deemed these acceptable losses, for the only thing that mattered was to deliver ''Fourth Horseman'' and its cargo of 11,000 Astartes to Protarkos.