Jovian Grenadiers
The Jovian Grenadiers were Imperial Army Regiments recruited from Jupiter during the Great Crusade and Horus Heresy.[1a]
History
When the Heresy's Schism of Mars occurred, four sub-cohorts drawn from the 19th Cohort of the Solar Auxilia, the Crimson Nova, took part in the Imperium's efforts to evacuate Loyalists and supplies from the besieged Forge World[2a]. Over fifteen thousand Grenadiers would be placed under the command of the Imperial Fists Captain Camba-Diaz, during the invasion, and they aided his two Companies in raiding Mars' Mondus Gamma Forge Complex for supplies. It was held by the Traitor Tech Priest Lukas Chrom, however, and while Diaz's raid had caught him by surprise, Chrom quickly recovered and unleashed his forces against the Imperials.[1a] The Traitors vastly outnumbered them and this resulted in the Grenadiers and the Imperial Fists suffering heavy losses. But with every second they fought on, vital supplies were evacuated from the forge. The Imperials soon began to be overwhelmed by Chrom's forces, though, and Captain Diaz had to order them to retreat before they were all killed by the Traitors. While the raid had resulted in a great loss of life, for the Grenadiers and the Imperial Fists, it had succeeded in evacuating a great deal of supplies for the Imperium.[1b]
The Saturnyne Grudge
The inhabitants of the moons of Jupiter and Saturn bear a great grudge between each other, such that during the Great Crusade and the Horus Heresy commanders would avoid assigning troops hailing from both worlds to the same warzone lest friendly fire occur. The grudge originates in the earliest days of the Great Crusade, during the unification of the Sol System. The Emperor's forces fought a years-long war against the Jovian people, whereas the inhabitants of Saturn surrendered and joined the nascent Imperium after a short conflict. While both the warriors of Jupiter and Saturn were similar, and that style of warfare formed the basis of the Solar Auxilia, it was the Saturnine Hoplites who were granted the honour of being known as the precursors of the entire Auxilia, along with the first ten cohort numerals. This remained a bitter point of contention between these two peoples well into the Horus Heresy. [2b] [3]