Imperium defeat Tyranid incursion on Helos Majoris

As 06.023M42 began the Imperium remained overstretched despite the victory on Mordecai Secundus. Inquisitor Cyrus Esquerra had advocated for pulling back from the Rifts of Hecate, but was overruled by Lord Inquisitor Huron who wanted to continue the crusade to the Eastern Fringe. The "crusade" was not in any way a large force, but the Ordo Xenos Lord Inquisitor had his own reasons for continuing the expansion of the Imperium despite the logistical problems.

The invasion of the Zadoc subsector forced Lord Admiral Jellicoe to pull back fleet assets from the Hadron Expanse, leaving the region dangerously exposed, but the withdrawal of the Tau from Ergura's Fall ensured Huron's view prevailed.

The Imperial bases in the Rifts of Hecate centred on the systems of Ferrosiun and Helos Majoris. In early 06.023M42 the latter system came under assault from a splinter of Hive Fleet Poseidon. The splinter force was particularly large and without a fleet to prevent the xenos from landing on the world, the Imperium were forced into a ground war as the alien creatures flooded onto the world. Fortunately for the Crusade, general Maximus had assigned a large proportion of his Imperial Guard to Helos Majoris, and they were able to construct significant defences.

The xenos creatures repeatedly smashed into prepared trench lines, taking heavy casualties, but biovore artillery gradually thinned out the defenders. A counter attack using a hades tunnelling drill failed to achieve its objective, but the battle was eventually turned by the army commander, and his command staff including a commissar. their company of one hundred men was whittled down to just five, but they held onto a key defensive position despite repeated xenos assaults. Unable to break through the imperial lines the Hive Mind withdrew, abandoning their remaining creatures which were exterminated in short order. Helos Majoris had been defended from the Tyranids for now, and general Maximus ordered the defences enhanced.