"Look upon me and know that I can slay you at will. You have no defense save one: to look into the darkness at the back of your own mind. There, you will find Father Nurgle waiting to offer you life in return for your submission. Deny him, and you are mine."
- Typhus the Traveller
Death Guard, the 14th legion is a traitor legion, formerly known as Dusk Raiders and one of the most terrifying traitor legions in the world of 40k. Unlike their brothers from different legions, Death Guards are known for their vile spread of plagues as each step they walk over the land, corruption, and disease itself sickens the world itself.
Before their corruption to the Chaos, 14th was known for its toughness and resilience within Imperium Space Marine Legions. Their traditional military doctrine is to attack at nightfall, earning the title, 'Dusk Raiders'. They were an unstoppable and relentless force within Imperium as they were an unstoppable force of nature on the battlefield. Unfortunately, this all when their gene-father, Primarch Mortarion the Pale King took over the 14th and changed the name from Dusk Raiders to Death Guard.
With the name changed to Death Guard, the once proud and right-hand legion of the Emperor forever changed when Mortarion entered the Imperium. Death Guard became a sheer relentless instrument of war. There was no strategy, no maneuvering pattern to confuse the enemy, or initiative to use the environment or situation to take advantage. Simply, the 14th legion stood the ground, waiting for the enemy to come to them and endure until the enemy falter before launching a counterattack.
Mortarion's warfare is based on his experience in his homeworld Barbarus and hugely favors the idea that the strongest recruits can only be found in Barbarus. Because Mortarion's homeworld is known for being a poisonous world, many of the natives in this world are gifted to withstand the poisonous environments. For this reason, Mortarion only recruits his future Space Marines from his homeworld, making them loyal to him, not the Imperium or his father, the Emperor.
When Mortarion and his legion fell into the corruption of Chaos, the one who waited for them was no one but Nurgle the Plague God. To twist the wound that will never recover, the one who actually brought the 14th legion to Plague Lord wasn't Mortarion but his first captain, Typhus the Traveller.
Typhus's betrayal of his brothers and gene-father greatly rewards him as he became the Herald of Nurgle. As he was the first one to be corrupted by the Nurgle, his reign and terror ran through the entire galaxy for ten thousand years. In the recent event, Typhus even rivals his own gene-father for the favor of Nurgle and command of the Death Guard.
As for Mortarion, the event of Ultima Segmentum gave him an opportunity to declare war against the Realm of Ultramar. The Plague Wars became a personal war between Mortarion and his brother Roboute Guilliman the Avenging Son as two Primarchs went face to face against each other. It is Plague Wars where the true terror of the Death Guard came to light as their ability to withstand lethal wounds and the spread of diseases corrupt world after world.
The Death Guard's Plague Marines and their new weapons brought new terror and destruction to both living and the world itself. Toxic blight grenades eat away even the armor and fill the air with noxious clouds of blinding and pathogenic spores. To make this worse, the grenade is made out of severed heads of fallen enemies and filled with cocktails of diseases, blood, pus, acid, and other vile creations (And this is only a grenade).
The spread of Nurgle's plagues isn't just diseases and sicknesses of all kinds. The plague itself is mixed with warp magic and able to root itself deep in the ground to maintain the corruption for a long period of time.
Many of the loyal Space Marines mention how they can smell the disease in their helmet even though it was air sealed and have dedicated air supplies for the power armor. Unknown to them, their armor couldn't stop the warp magic from entering their armor, slowly infecting them from the inside.
The mix of plague and warp magic became a perfect combination for the Death Guard as even if they were defeated, their destruction of the world still made them victors of the battle, slowly killing the survivors and making the world inhabitable for a long period of time.
Lastly, Death Guard can use the plague known as Zombie Plague also known as Curse of Unbelief. A warp-spawned infection that spread a horde of undead zombies and is very infectious when used in populated cities. They are the frontline soldiers and literal meat shields for the Nurgle faction as they will overwhelm the enemies and continue to spread the zombie plague to the other worlds.
"Say what you like about the Fourteenth Legion. They are mean, ugly bastards but tenacious. There's no one else I'd rather have by my side in a war of attrition, and almost anyone else I'd rather have against me."
- Ferrus Manus, Primarch of the Iron Hands
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"Have Krieg use the combustion rounds instead of explosives. I will not have the entire province exposed to plague spores due to shells from our own forces. Burn the whole fortress with fire and kill everything within. The 14th is there in the fortress and there are no living beings we can rescue." William made his decision on how to start the final campaign. After his order was given, the entire 333rd Krieg company start their artillery fire and the sound of bombardment shook the sky and earth itself.
The field near the fortress began to catch fire and eventually, the wall and outer buildings were engulfed with raging flames. To everyone's surprise, there was no exchange of fire from the enemy instead fortress gate opened, and thousands of people step out towards William's base.
"My lord. They are thousands of mixed civilians and soldiers. I don't think they are alive." One of the officers of the Imperial Guards reports back after observing the situation. William expected this from the Death Guard as they use expendable troops to deplete enemy ammunitions and resources. The war of attrition is what the 14th is good at but unfortunately for them, William's Space Marines are something different and new.
William already knew how the Plague Marines use plague and warp to their advantage. William on the other hand has a countermeasure to cancel the warp magic, making the plague normal plague to be purged after the battle.
Following the order from the Chapter Master, the Blacksouls (Null Marines) already surrounded the fortress, outside of the artillery range but close enough to react immediately when the enemy forces engage outside of the wall.
With new genetic improvements to resist diseases and advanced medical technology, the Blacksouls are capable of fighting the Plague Marines better than firstborn Space Marines. Not to mention, Liberians' blank abilities can neutralize the warp, making the enemy die for real.
"Redirect the bombardment into fortress entrance. They are stuck in the bottleneck and wasting their troops for nothing." Lord Creed, as supreme commander of the Imperial Guardsmen, replied with new order for the Krieg. Next to him, Lord Commissar Cain stands as he double-checks his laspistol, expecting the unexpected as his luck tends to put him in danger.
'My hand is tingling and I know this means trouble. What is it?' Cain observes his mind to see what is causing his subconscious mind to go on alert. The fortress is one way in and there is no enemy reinforcement according to the report.
"New report! Enemy drop pods incoming!" The second intel officer observing the radar made a new report as the sound barrier broke half a second later. Dozen green drop pods drop between incoming zombies and Blacksouls, surrounding the Space Marines on two different fronts. When the dozen of pod doors opened, Plague Marines emerged from them and two factions engaged in battle while zombies continue to come out of the fortress.
"Continue the artillery bombardment. We must not allow the enemies to surround the Astartes. Check for additional pods, there must have come from somewhere." Lord Creed ordered his officers to regain control of the battlefield while William send his own orders to the Blacksouls to focus new enemy with no mercy.
"Lord Creed, look over there in the sky." Cain point his finger up above the sky which cloud began to move away. Up in the sky, hidden among the clouds, a large ship can be seen and it can be identified without looking through binoculars.
"By the Golden Throne! That is a Battle Barge! How did we not detect that ship from our sensor?" One of the senior officers demanded an answer from the intel officers but that wasn't important at the moment. The enemy has the advantage in the sky and William's side doesn't. If the enemy decided to start their own bombardment, they are in serious trouble as William doesn't have a countermeasure to protect from sky bombardment.
"Magos, is the battle barge shielded?"
"Yes my lord, in fact, there is a second incoming vessel approaching from behind us. It doesn't look like it belongs to the enemy." Magos's last comment alert William as his plan to board the enemy ship is scraped and turns around to see the new vessel approaching.
Above the sky, a Necron's Night Scythe fast approach the Death Guard's battle barge. Armed with a twin-linked tesla destructor, the Night Scythe fire its weapons at the enemy ship. Lighting hit the enemy ship's shield but soon the shield shattered and melts the ship's armor. Due to the superior speed of the Necron ship, the battle barge couldn't do much as they didn't anticipate a Necron to interfere and lack of options to fight back on short notice.
Death Guard's battle barge launch a few fighters to counter the Necron ship but it was useless as lighting from the tesla destructor caused a chain reaction, destroying the fighters before they could fight back.
"Hello, Champion. I propose a truce for a moment until we take care of your corrupted brothers." Trazyn the Infinite appeared on William's helmet screen as he appear casually sitting on his command throne. Compare to what William saw previously, Trazyn looked beat up and show multiple scratches on his metal body but it didn't seem to bother him as his attitude and tone were friendly.
"Trazyn the Infinite, I should have known it was you. Why are you here interfering with my fight? Lacking collection of Death Guard?"
"Funny. I was fighting them long after our… encounter. Let's just say I have my own reason, oh and this is for killing me last time." With a petty tone, Trazyn the Infinite teleported William and his royal guards to Death Guard's battle barge and flew off from further engagement. Leaving William in the hands of the 14th Legion, Trazyn knew his time will come to capture both the champion and the Living Saint. He just needs to wear out the beast before delivering the final blow.