Plague Marines - History: The origins of the Plague Marines can be traced back to the early 31st Millennium. During the opening days of the Horus Heresy, Ignatius Grulgor was the commander (captain) of the Death Guard Legion's 2nd Grand Company.During the massacre of the Traitor Legions' Loyalists on Isstvan III that initiated the Heresy, Grulgor was posted on the Imperial frigate Eisenstein to kill the Loyalist Captain Nathaniel Garro and his hundred-strong company of Death Guard Astartes.Grulgor was initially killed in a firefight on the gun decks of the Eisenstein, after a stray Bolt Pistol shot released the Life-Eater virus within a Virus Bomb that had been intended to be used against the Loyalist Astartes on Isstvan III.After the successful escape of the Eisenstein and the following trip through the Warp, the body of Grulgor was reanimated by the machinations of Nurgle as the first of the Plague Marines.Following a desperate battle, Grulgor's body was destroyed after the Eisenstein made an emergency transition into realspace. His soul banished into the Warp, the Plague Lord eventually raised Grulgor once more as one of its Daemon Princes. In 999.M41 Grulgor would return to haunt the Imperium during the forces of Chaos' assault upon Medusa V.The Plague Marines later appeared en masse at the start of the Siege of Terra late in the Horus Heresy. The Death Guard Legion had become becalmed and trapped within the Warp where the virulent Destroyer Plague, later known to the Imperium as Nurgle's Rot, attacked their bodies.For the Death Guard, there was nothing more terrifying than the plague that rendered their legendary resilience meaningless. These were warriors who had been immune to the diseases, contagions, toxins and pollutions that bedevilled normal men.What the Death Guard endured was unimaginable, yet none suffered more than Mortarion himself. Unable to endure the suffering any longer, the primarch and his Legion offered themselves up to the service of the Lord of Decay in return for their lives.Their bodies became bloated and swollen with the corruption, festering within them, but they no longer felt the agony of the Warp-pox and did not die from the horrific symptoms.When the Death Guard Legion fleet emerged from the Warp above Terra, they bore little resemblance to the proud Astartes who had entered.Their once-gleaming grey armour and the proud heraldry of the once-Imperial champions was no more; in their stead was a sickly pall of greenish hue. Each Astartes was now a bloated grotesque, covered in pock-marks and boils, scabs and putrescent sores.They bore the stink of corruption as the very air about them was clouded with swarming flies. Even their weapons and war machines had been mutated by the energies of the Warp and were now powered by the sickly sorcery of Chaos, glowing with lambent green energy and oozing gangrenous pus. The Death Guard had become walking pestilence carriers; they had become Plague Marines.Since that bygone era, many Chaos Space Marines have dedicated themselves to Nurgle, though few achieve the vaunted ranks of the Death Guard. Those who truly wish to join these most foetid of followers must first prove their loyalty to the Daemon Primarch Mortarion. Only then will Nurgle bestow upon them the corrupting plague that created the Plague Marines.Outside of the Death Guard, a favoured few Chaos Sorcerers of Nurgle know the secrets of the Plague Marines, and Abaddon of the Black Legion has won many of these spellcasters to his cause. In return for loyalty and long service, these so-called "blight mages" will bestow their pestilent gifts upon other Chaos Space Marines in the cause of Chaos Undivided.