The Death Guard are going to battle in War of the Spider – So let’s take a long look at their Primarch: Mortarion!
Mortarion (also known as the Death Lord) was one of the original twenty Primarchs. He was given command of the Death Guard Legion on the arrival of the Emperor to his world of Barbarus but turned to the forces of Chaos during the Horus Heresy.
The only consistent information regarding Mortarion and his homeworld come from a single source: the Stygian Scrolls of Lackland Thorn, a historian and polymath attached to the explorator fleet that discovered Barbarus.
Mortarion crash landed on the world of Barbarus. He came to rest at the site of a huge battle fought across a vast plain. All around him were strewn the bodies of the dead and dying for miles in all directions. Barbarus was constantly covered in a poisonous fog and the mountains were ruled by fierce warlords. The normal humans, dropped off millennia before, were forced to live in the lowest areas of the planet, amidst the choking fog. They were condemned to an endless life of servitude and were in constant fear of those who moved above them.
Mortarion wouldn’t be the same if he’d landed on a planet of chocolate, instead of death and plague…
The winner of the battle in which Mortarion had landed was the greatest of the warlords. He was revelling in his victory until the silence was shattered by the scream of a child. It is said this warlord walked the battlefield for a day searching for the child, not stopping once until he found it. For a moment he considered killing the child, but he realised that no human should be able to breath at this height, let alone cry out. He considered what he had found, and then bundled the child up and carried it from the carnage. He now had a son, something he had craved for years despite his dark magical powers. The warlord christened the child Mortarion, child of death.
The warlord tested how high the child could survive in the poisonous atmosphere of Barbarus and then erected a massive wall of black iron. He then moved his mansion past this to keep it from the child. Perhaps he knew the child was better than him and that one day he would come for the warlord, or perhaps he was afraid of the small child able to breath where no other of his kind could. Whatever he felt, he trained the child in his image. He taught everything of warfare to Mortarion. He was constantly at the front fighting against all of the other warlords’ armies, sometimes of undead humans, sometimes of more daemonic creatures. Mortarion was still human though, and he sought to know of those who dwelled below the layer of fog. Eventually Mortarion escaped from his holdings and descended the mountain, the warlord bellowing after him of his treachery and that to return would mean death.
As Mortarion descended, he began to realise he had found his people. He smelt the scent of food for the first time, he saw people unobstructed by the fog and for the first time he heard laughter, real laughter, not that of the victorious warlord’s. He realised that the prey that the warlords fought over was his own people, and with this came a sense of hatred and he vowed to give them justice over their oppressors.
As Mortarion grew he taught the villagers all he knew of warfare. Word of his knowledge and exploits spread and people came from far and wide to learn from him. Soon, villages were becoming strongholds and the villagers were more effective defenders. Eventually, Mortarion began to move from village to village, teaching along the way and if need be, defend the settlements. His ultimate vengeance was always denied to him because of the fog that prevented the humans from pushing home their attacks.
Mortarion then recruited the strongest and most resilient of warriors from the villages he went to. He formed them into elite units and drilled them himself. He turned blacksmiths from tool-working to weapons-making when time allowed and had them craft armour. He also armed his warriors with crude air filtration apparatus. It is said that the next attack that descended from the mountains above was repulsed quickly and Mortarion, leading his Death Guard, as they had become known, followed them into the fog above, massacring the remaining forces and killing the warlord. For the first time in history, Mortarion had led the people into the toxic fog and survived. Mortarion continued to improve the breathing apparatus and campaigned ever higher into the fog. The constant exposure to the toxins hardened his warriors, a useful and transferable skill retained by the Death Guard
It was said that Mortarion brought his relentlessness to the Death Guard legion and they followed his ideals. He only ever found friendship in two other Primarchs, Night Haunter and Horus. So close did Mortarion and Horus become that the ever watchful Roboute Guilliman of the Ultramarines and Corax of the Raven Guard approached the Emperor with concerns as to where Mortarion’s loyalties lay. The Emperor waved it aside with a hand gesture; loyalty to Horus was loyalty to the Emperor. Meanwhile, Mortarion was frequently critical of Magnus the Red over his use of Librarians and was one of the chief voices to ban Psykers among the Astartes Legions at the Council of Nikea. Mortarion expressed a hatred of all things related to the Warp, and felt betrayed when he managed to sneak into the Imperial Palace and discovered the Golden Throne under construction. However after Malcador explained that the purpose of the Golden Throne was to remove mankind’s need of the Warp, Mortarion was put more at ease. Mortarion also clashed with other Primarch’s who he felt had upbringings far easier than his hell on Barbarus, particularly Sanguinius, Jaghatai Khan, and Fulgrim.
Horus found Mortarion more difficult to bring to his cause than either Angron or Fulgrim, and for a time it seemed the Warmaster may have failed to convince the Lord of the Death Guard. However Horus at last found a chink in Mortarion’s armor, he was beginning to see the Emperor as having been corrupted with power and now was just another tyrant drunk with power. Indeed, Mortarion had become disgusted with what exactly the Emperor was, considering him a Warp-tainted “aberration” like his tyrant adopted father. Horus also used Mortarion’s distrust of the Warp to his advantage, arguing that the Emperor had used the Warp in the creation of the Primarchs. Horus eventually used these doubts to bring Mortarion to his cause. Mortarion led his Legion in their betrayal of the Imperium at the Battle of Isstvan III and Drop Site Massacre. He later came to blows with Jaghatai Khan on Prospero after failing to convince him to join with them in rebellion. During the fight the two Primarch’s were able to challenge the other, with the Great Khan proving faster and the Death Lord proving more durable. Following the battle, Mortarion abandoned his pursuit of the White Scars and instead began a spiteful purge of the systems surrounding Prospero. During the purge, Mortarion encountered a Daemon possessing the body of a woman and was forced to kill it using his innate psychic abilities despite it being against Imperial (and by this point, his very own) dogma. Realizing that the Emperor had lied to him about the Empyrean, Mortarion vowed to master it.
By the time of the Battle of the Kalium Gate late in the Heresy, Mortarion’s forbidden knowledge had grown considerably. He experimented with both Xenos and Chaos artifacts, vowing to remain pure through understanding. At this same time he was tasked with Horus to find and destroy the White Scars, who had been harrying the traitor lines since the events on Prospero. Mortarion was initially reluctant, but was moved by Horus’ declaration that he was the only Primarch the Warmaster still could rely on and was eager to settle the score with the Khan anyway. In the subsequent Battle of Catallus, the joint Death Guard-Emperor’s Children fleet led by Mortarion cornered the White Scars fleet at the Dark Glass artifact. But as Mortarion boarded Jaghatai’s flagship, the Swordstorm, he discovered the ship abandoned save for a contingent of suicidal Sagyar Mazan warriors. Worse still for the Primarch, the reactors of the Swordstorm had been set to overload and the Khan had since evacuated to the Battleship Lance of Heaven, which was leading the escape of the loyalist fleet into the Webway. Unable to escape thanks to the Sagyar Mazan and the vessels reactivated Void Shields, Mortarion led the massacre of the Scars suicidal rear guard while directing his fleet to combine its fire and reduce the Swordstorms shields. When the shields were depleted shortly after he personally killed Torghun Khan, Mortarion barely teleported off the Swordstorm before it exploded. Following the battle, Mortarion realized that his divided fleet had hampered the war effort and ordered Eidolon to find Calas Typhon and his splinter fleet.
After these campaigns, Mortarion rejoined the primary Death Guard fleet under Calas Typhon, who was waging the Dark Angels fleet in a campaign of misdirection in the aftermath of the Battle of Perditus. Eventually with the entire Death Guard fleet, Mortarion set off to Terra to join the siege. Unfortunately the fleet was caught in an impenetrable warp storm, the navigators not being able to find a way through the warp or a way back into real space. The fleet was reduced to drifting, and in that time the Destroyer came. The plague that came could not be resisted, something that terrified Mortarion and the Death Guard. It transformed them into bloated mutants, yet none could die, their own body being their undoing. None suffered more than Mortarion, for it was like being on the mountain top again, surrendering to the toxins, but this time without the Emperor to save him. Eventually, Mortarion could suffer no more and gave himself to Chaos. Father Nurgle responded and took the legion and Mortarion as his own.
What emerged from the warp bore little resemblance to what had gone in. The Marines’ once gleaming armour was corroded and shattered, barely containing their bloated, pustule covered bodies. Their weapons and armour were powered by the energies of Chaos and they became known as the Plague Marines, although they would still use the name Death Guard. After Horus was defeated, Mortarion led his forces, in an ordered formation, back to the Eye of Terror. Mortarion claimed the Plague Planet as his new world and it is ideal for launching attacks on the real world. He shaped it so well that Nurgle promoted him to Daemon Prince. Mortarion got what he wanted, a world of his own. He ruled over a toxic death world of poison, horror and misery. He had come home.