this is some of the death guard lore please find this

Symbol of the Dusk Raiders The base gene-seed stock of the Dusk Raiders, originally known as the XIVth Legion, came from Terra or more specifically the warlike and tough clans of Albia. In the Unification Wars the XIVth Legion quickly developed the use of tactics and methods of warfare that their ironside fore-bearers would have found familiar. Operating in the role of heavy infantry, they were experts at survival, endurance, and stubborn defense. Their grey Power Armour began to carry battle decorations as well as the modified imagery of Albia. As the Unification Wars came to an end and the Great Crusade began, the Emperor gave them the title of the Dusk Raiders, a nod to their use of the ancient Albian tactic of conducting major ground attacks at twilight when the shift of light confused an enemy's watch and gathering shadow would advance across open ground.
The Dusk Raiders' armour was originally unpainted, but with their right arm and both shoulders coloured crimson. This was done with the intent to show their enemies that they were the Emperor's red right hand, relentless and unstoppable. Many enemies simply threw down their weapons at nightfall so they didn't have to fight the terrifying Dusk Raiders.
For more then eight decades the Dusk Raiders fought across the Galaxy in the Great Crusade, earning a fierce reputation by failing to reunite with their Primarch.




The Great Crusade Formation When Mortarion was found by the Emperor upon the troubled world of Barbarus, he was swiftly given control of his Legion. Upon first seeing them he told them, "You are my unbroken blades. You are the Death Guard." The Legion's name was then changed in accordance with this decree, and Mortarion's words engraved above the airlock door of the Battle Barge Reaper's Scythe in honour of the moment. While the Legion was known as the Death Guard formally, its older members referred to themselves as the Unbroken, after Mortarion's words, in a tradition that still continues.[26a] Mortarion based the new Death Guard on his armored toxin-resistant fighters of the same name that had fought beside him on Barbarus in the Overlord Wars. Their armour's colour was changed, and whilst their main armour remained unpainted, the trim colour became dark green. Mortarion's veterans of Barbarus formed the core of his new Legion.


Combat Disposition and Record Before the Horus Heresy, the Death Guard differed from the other 17 known Legions in that they had only seven Great Companies, although these held far more men than those of other Legions such as the Ultramarines or Space Wolves. There were three privileged titles held by captains of the Death Guard. The captain of the First Company was known as the First Captain, the captain of the Second Company was known as Commander, and the captain of the Seventh Company was known as Battle-Captain.
The Death Guard tended to be organised into units of foot-slogging infantry, rather than mechanised squads. Mortarion ensured that his men were well-equipped and highly-trained. He also ensured that they could fight in almost any kind of atmosphere, and placed little emphasis on specialised units using jump packs or bikes. The Death Guard did not have dedicated Assault and Tactical Squads. Every Marine was equipped with a bolter, bolt pistol and close combat weapon and told to fight with whatever weapon circumstance dictated. The Legion was also well known for its use of Terminator Armour. Possibly as a result of this, the Death Guard were highly successful at high-risk boarding and close-quarter operations such as space hulk clearance.



Hberesy-era Death Guard Marine By the time of the Horus Heresy, the Death Guard is known to have had roughly 95,000 Space Marines.




Tbhe Horus Heresy At the beginning of the Horus Heresy, many Death Guard who remained loyal to the Emperor were massacred on Isstvan III by their fellow Space Marines, including Captain Ullis Temeter. Roughly a third of the Legion was still loyal to the Emperor. Shortly after, they battled Imperial forces in the Drop Site Massacre. A number of Death Guard Marines, and one Luna Wolf who renounced his Sons of Horus status, led by Battle-Captain of the 7th Company Nathaniel Garro, remained loyal to the Emperor. They formed part of the crew of the Eisenstein, a frigate which ran the Traitor blockade in the Isstvan system in order to bring news of Horus' descent into Chaos to the Emperor on Terra




Dburing the Horus Heresy, the Death Guard joined Warmaster Horus in many battles and raids on the Imperium. The Lord of Death split his fleet, commanding one himself and Calas Typhon the other. Mortarion's smaller fleet led a failed attempt on Prospero to convince Jaghatai Khan and the White Scars to join with them, and the Mortarion found himself in combat with the Great Khan. After the White Scars managed to abandon the Death Guard fleet, Mortarion had his Legion embark on a spiteful purge of the Prospero System. Mortarion then fought alongside Horus in the Battle of Dwell and Battle of Molech before rejoining Typhon's main fleet, which had been waging a campaign of misdirection and misery against the Dark Angels since the Battle of Perditus. Later, Horus himself tasked Mortarion with finding and destroying the White Scars. Eager to settle the score with the Great Khan, the Death Guard and Emperor's Children allies under Eidolon cornered the Scars at the Dark Glass, but failed to destroy them in the Battle of Catallus. Angered, Mortarion realized that his divided legion was hampering his war effort and ordered Eidolon to find Typhon and his splinter fleet. On the world of Ynyx, Typhon again showed himself and was secretly disappointed that Mortarion and his forces had yet to embrace the Ruinious Powers.




Fball of the Death Guard When the Death Guard's fleet embarked for Terra Typhon made his move. The First Captain had his Grave Wardens frame and kill the Navigators, whom he alleged remained loyal to the Emperor, and assured his Primarch that he could lead the fleet to Terra without their help using his own corps of Librarians.Instead, he led them into a trap - becalming the Death Guard fleet in the warp, adrift, helpless and at the mercy of Chaos. Then came the Destroyer Plague and the Death Guard were struck down, but Typhon received his reward from "Grandfather Nurgle" and he absorbed the full power of the plague from Ignatius Grulgor. His body became home to the flies of Nurgle, his armour a hive of pestilence. He then became Typhus, Herald of Nurgle and the Host of the Destroyer Hive. Mortarion himself succumb to the Destroyer Plague, facing its agony with his sons. Nurgle himself came before Mortarion, stating that if he did not pledge himself to the Plague God they would be doomed to torturous undeath for all eternity. Mortarion broke and pledged himself to Nurgle. Though the agony ended, the Death Guard were remade into a shambling army of diseased Plague Marines, bearing little resemblance to what first entered the Warp. Mortarion himself was remade into a Daemon Prince.




Tbhe forces of Horus besieged Terra and the Imperial Palace itself. After a breach in the Palace defensive wall was forced by Titans of the Legio Mortis Titan Legion, the Traitor Legions, including the Death Guard, poured into the breach only to be met by loyalist forces led by the Primarchs Rogal Dorn and Sanguinius. It is recorded that Mortarion personally led his pustulent Plague Marines into the thickest fighting that day. Following the departure of Perturabo and the Iron Warriors from the battle, Horus gave Mortarion command of the Lion's Gate Spaceport. However this was assailed in a sudden counterattack by Jaghatai Khan and the White Scars. At the height of the fighting, Mortarion and Jaghatai Khan dueled. At the end of the battle a badly wounded Jaghatai Khan managed to banish Mortarion to the Warp, while the loyalist Primarch himself grievously wounded. After the banishing of Mortarion command of the legion fell to Typhus.




Pblague Marines Horus Heresy Aftermath After Horus' defeat, Mortarion led his Death Guard in a campaign of destruction over a score of planets, until finally retreating into the Eye of Terror. Here he received Nurgle's ultimate reward and became a full-fledged Daemon Prince, ruling over one of Nurgle's greatest Plague Worlds in the Eye of Terror. Mortarion sends out fleets of Plague Ships into the Warp to carry their contagions throughout the galaxy. Concerned himself with matters of the Warp more and more, Mortarion has periodically returned to lead his Legion but in his absence it has largely splintered into many smaller warbands.




Hbowever though it was factionalized, the Death Guard never fully disintegrated as a cohesive force. Their fragments continued to fight under a singular purpose, and never resorted to the civil in-fighting of many other Traitor Legions. The Death Guard remains one of the most ordered and coherent of all the surviving Traitor Legion's.At the end of the 41st Millennium, Mortarion senses his Brother Primarch's rebirth and reasserted direct control over the Death Guard once more. The Death Guard launched a major assault on Ultramar in what became known as the Plague Wars.