The Tome of Decay (2014), p25-26 — The Death Guard

Though now considered one of the Imperium's most abhorrent foes, the Death Guard were once counted among the most relentless and resolute of the Emperor's warriors. The cryptic Stygian Scrolls claim the Legion hailed from the planet Barbarus, a toxic world wreathed in a perpetual poisonous fog. As a result, the planet's inhabitants became extremely resilient to their poisonous home world, a trait that would eventually give rise to the Death Guard's infamous ability to operate in even the most toxic warzones. This hardy constitution, combined with a grimly stoic demeanour and brutally efficient infantry tactics, made the Death Guard one of the most determined and reliable forces within the Great Crusade.

Yet when Horus led half the Space Marine Legions in rebellion against the Emperor, he was able to sway Mortarion, the Death Guard's pallid and grim Primarch, to join him in tearing to the ground all that his father had accomplished. What exactly motivated Mortarion to betray the Imperium is lost to history, yet he and his warriors eagerly joined the other traitors in their campaign of destruction, crossing into the Warp en masse to aid in the assault on Holy Terra.

However, shortly after their transition, the Death Guard were becalmed within the fickle Warp tides, while a strange and devastating plague of unprecedented virulence ravaged the Legion and their attendant fleet. Even the legendary physiologies of the Space Marines could not save them as one by one each of the Death Guard was overcome, their superhuman bodies bloated and distended as the foul contagion transformed them into shambling, diseased grotesques.

Yet none are believed to have suffered as greatly as Mortarion, who was forced to watch his progeny stumble in unending anguish through the disease choked confines of their helpless vessels without hope of escape or death. In desperation, Mortarion offered up his soul and the souls of the remaining Death Guard to the Warp in exchange for his Legion's salvation, and it was Nurgle, Lord of Disease and Decay, who answered his prayer, saving the Death Guard and ensuring their eternal damnation.

What eventually emerged from the Warp within their filth-covered plague ships were not the stoic and austere Death Guard of old, but the first and most deadly of the Plague Marines. Led by their Primarch, the transformed Legion burst forth upon the Emperor's Palace of Terra like a tide of putrid corruption, their disease-encrusted bulks and rust-covered weapons wreaking a devastating toll upon the Imperial defenders.

The Heralds of Decay

In the wake of Horus's defeat, the Death Guard retreated to the Eye of Terror alongside the other Traitor Legions, their steadfast demeanour allowing them to avoid the disarray and anarchy that afflicted many of their traitor brethren. Upon entering the Warp, they laid claim to a blighted world near the borders of reality now known as the Plague Planet. The Death Guard are said to dwell there still, and it is from this poisonous rock that the Legion continues to strike out at their Imperial enemies, their massive plague ships bursting with diseased followers eager to bring despair and desolation to mankind. Those insane and corrupted individuals who claim to have set foot upon it say it is a toxic world of corruption and pestilence whose skeletal ruler dwells within his wrought-iron bastion upon the world's highest peak.

Since their fall, the Legion has utterly dedicated itself to propagating Nurgle's corruption, its diseased fleets spewing from the Warp to spread his vile plagues across countless worlds. In battle, they are as utterly relentless as ever, inexorably advancing in the face of withering fire while using their rust-covered bolters and poisonous Plague Knives to brutally dispatch their foes. Their bloated and diseased bodies are immune to fear and pain, often allowing them to causally ignore wounds which would kill lesser men.

Throughout their centuries of raiding, the Legion has gradually split into smaller and smaller units, each led by a particularly deadly Champion of Nurgle in addition to the untold numbers of foetid, Warp-spawned servants that accompany them. In keeping with their corrupt heritage, the Death Guard primarily fight on foot, relying heavily on infantry tactics and their own diseased physiologies to overpower their enemies. Many of these repulsive warriors are the same traitors who burst forth from the Warp during the fabled Battle of Terra centuries ago, while others are more recent converts who have sworn allegiance to both Mortarion and his noxious patron.

Scattered warbands of Death Guard frequently operate within and around the Screaming Vortex, ever eager to reduce the many worlds surrounding those unnatural currents to stinking morasses of putrefaction. Though few in number, they frequently swell their ranks with denizens of the Vortex who wish to spread Grandfather Nurgle's bounty as well as the numerous Traitor Space Marines who have embraced the path of decay. Yet there is a change coming within the Vortex, with many isolated warbands uniting beneath the pestilent banner of a malevolent new champion who has emerged from the eternal warzones that surround the Calixis Sector.

Known only as Buorgdius, legend has it that he was once a proud captain of a Space Marine purgation force that was sent to facilitate the eradication of Chaos forces within the Acheros Salient of the Jericho Reach. After months of brutal campaigning, a rogue plague ship unexpectedly burst forth from the Warp and rammed his Strike Cruiser before vomiting its rotting warriors directly into the vessel's interior. It is said that the Captain fought with terrible fury, cutting down all manner of plague-ridden monstrosities while enduring the foul swarms of flies and noxious clouds of contagion that choked every corridor and assailed his superhuman frame.

By the time he reached the bridge, the mighty warrior could barely stand, while behind him his battle brothers lay dead or dying and the servants of Nurgle ran rampant throughout the hallowed halls of the venerable Strike Cruiser. The bloated Daemon-thing that confronted him within that necrotic bubo laughed at the weakened Captain's plight and raised his massive weapon to strike the killing blow. In that moment, the Captain despaired, crying out in anguish and pleading for the strength to kill his foe. Suddenly unhindered by the innumerable infections that festered within his body, the Captain struck out with renewed vigour, smiting his opponent and claiming his place at the plague ship's helm.

Now he is a Champion of Nurgle whose plague fleet plies the outer fringes of the Screaming Vortex, unleashing its revolting warriors against those unfortunate enough to fall afoul of their diseased and leprous hulks. In combat, Buorgdius leads the reanimated corpses of his former Space Marine brethren into battle while wielding a massive mace crafted from the diseased bones of his unholy predecessor, and dripping with repellent Warp energies. Afterward, his undead warriors stuff the innumerable dead and dying into the filthy, dank plague holds of his vessels in order that they may moulder in the foetid darkness. In this way, the champion recruits many of his mightiest warriors, and he is said to offer a place in his warband to any who will but supplicate themselves before the Lord of Decay.