Doom of the Grous System

The Doom of the Grous System was a lamentable Imperial campaign that took place in the doomed Grous System in 419.M41, when it was set upon by an unnamed Tyranid Hive Fleet. Though the Emperor's Trident and

History
The Grous System was a tragedy, as the Imperium lost many valuable planets including an agri-world, forge-world, three civilised worlds, and an ocean world. The Great Devourer entered in system due to a genestealer cult that sent their xenos beacon that alerted a nearby hive ship to the system. With the Grous system so close to the Emperor's Trident homeworld, the chapter disengaged from all engagements to try and reach the system as fast they could. The genestealer cult revolted the authority on Grous IV, a civilised world fell into anarchy as tyranid reinforcement flooded the planet.

The Emperor's Trident sent almost their entire chapter to the Corako system as the 8th company was elsewhere. With 1,300 battle brothers in-system, Grous IV fell and on their way to Grous III, Chapter forces made planetfall on Grous III rallying to the capital until the majority of civilian populations evacuated. With the tyranid forces advancing on the capital with sections of the capital falling each day and casualties of the Emperor's Trident rising.

When the population of Grous III and Grous II was evacuated with the Forge world sending reinforcements to the Emperor's Trident with hundreds of thousands of guardsmen and Skitarii forces to Grous V the Emperor's Trident Chapter with Guardsmen/Skitarii holding off the tyranid forces at the capital planet while the rest of the system was devoured in that time. The fighting was so brutal and long lasting that some battle-brothers had to fight with fists and some resorted to looting weapons and ammo of their fallen brothers. With the last city falling the survivors grouped up to the Chapel of the Emperor's Light.

Many Battle-Brothers were ready to die as the Chaplains were performing prayers that were only used in funerary services of fallen brothers and serfs and similar takes in the communal vox, with many preparing to die and thinking that there chapter would die they all yelled at the top of the throats their ancient battle cry and all vowed to not retreat and die down to the last man. When the battle was at it peak, the sky rained drop-pods of two additional Space Marine chapters which had arrived to assist in the planet's defence. The chapters were able to push through the cordon of Tyranids outwards as the Emperor's Trident regrouped. The two chapters had been enroute to a couple nearby systems that had fallen under siege by the Traitor Legions, when they received the astropathic distress message from the Grous System.

The two chapters had encountered Grous refugees fleeing the doomed system. They told the Astartes that a fellow Astartes chapter had come to their aid, and although severely outnumbered, they refused to retreat. The system died when many refugee ships were caught by tyranids. When the chaptered reunited with one another as many of the companies were cut off from one another around the city, many had their armour heavily scarred and ruined with a number with missing limbs and destroyed. Even their colour scheme was scratched off, showing much of the original plain slate-grey colour beneath. With many chapter ships once full of battle-brothers, but now seemed almost empty, with the 3rd Company only having one survivor amongst it's number. The Emperor's Trident regrouped and re-armed, and eventually traveled back to the Grous System alongside their fellow Chapter in order to deal with large-scale xenos attack once and for all.