When all twenty-two Mastodons exited the hanger and stop just in front of the command center, where all the Astartes waiting at, Atharion, who's standing with the Captains, can see confusion and surprise in their eyes.
This also can be see on the Techmarines from their respective command squads as they will definitely learn about Mastodons when they studying on Mars.
But, there's only excitement and curiosity from those normal Astartes while the Sergeants also curios about the machine, but they also understand that something like this, where none of them have seen deploy by any of the fellow Chapters, even from the First Founding, may be a war-machine that loss to time.
But, when a Chapter that just founded in Thirteenth Founding is able to field such machine in such numbers, anyone who see these will only grow suspicious of it.
But, true to what Atharion speculated, none of them plan on saying this to their squad members, even the Captains and the Techmarines have planning on telling anyone.
The Sergeants only plan to have a conversations with their Captains when these over, the Captains plan to inform their Chapter Masters what they saw, while the Techmarines only wish that they have the chance to closely observe the Mastodon.
"Mastodon," the Warsmith said as he stood in front of the Mastodon. "a heavy tank use during the Great Crusade and the Heresy, capable of transporting 40 Astartes or 20 Terminators or 2 Dreadnoughts."
The Warsmith continue to explain the Mastodon to them. This mainly to let them understand what the machine is and it is safe to enter it, and know that it can safely transport all of them to the wall even under heavy fire.
The moment he finish the introduction, the Techmarines immediately flood to his side, wanting to gain more information about the Mastodon and more importantly, wanting to try their luck if they have the chance to closely observe the machine.
The Captains instead look at each other, seemingly confirm their suspicious.
"Make sure all of your men are prepare," Atharion said to the Captains as he looking at the Warsmith that being surrounded. "we must finish this now."
===
"Why should we keep standing here?" a traitor guard said. "it's not like the servant of the Corpse Emperor will breach the void shield."
"We have our order," another traitor guard said, seemigly their leader, holding a power sword and a plasma pistol. "but if you want to try the wrath of our master, then be my guest."
The guard did not say anything further. Instead, he let out a frustrated huff and adjusted his grip on his lasgun.
Around them, hundreds of traitor guardsmen remained stationed along the western wall.
Heavy bolters sat behind reinforced emplacements.
Lascannon teams watched the killing grounds beyond the fortress.
Autocannon batteries swept the horizon for movement.
Above them, the void shield shimmered faintly across the sky, protecting the fortress from the endless artillery barrage that had pounded it for months.
"See?" the guardsman said after a while. "Nothing. Same thing every day."
The officer was about to reply when a distant rumble reached them.
At first, nobody paid attention.
The fortress had been under bombardment for two months.
Explosions and tremors had become normal.
But the sound continued.
Growing louder.
Growing heavier.
Soon, even the guardsmen nearest the battlements turned their heads toward the horizon.
"What is that?"
The officer narrowed his eyes.
Beyond the smoke and dust, shapes were appearing.
Large shapes.
Very large.
One by one.
Then dozens.
As they emerged from the haze, the officer felt his stomach tighten.
"What in the Warp..."
The vehicles continued forward without slowing.
The Lascannon beams, missiles and heavy bolter rounds all not even touch the vehicles hull.
The void shield around the vehicles flashed repeatedly as they absorbed the incoming fire.
As the Mastodons drew closer, the morale of the defenders began to crumble.
Some traitor guardsmen abandoned their positions outright.
Others simply froze, staring at the advancing giants.
Seeing what was happening, several officers drew their weapons and executed the cowards on the spot.
For a moment, discipline returned.
The firing lines stabilized.
But it was only temporary.
Nothing they did could stop the fear spreading through the ranks.
The Mastodons simply kept coming.
When the colossal transports finally crossed through the fortress void shield, their weapons immediately came alive.
Twin sponson-mounted lascannons fired in coordinated bursts, destroying heavy weapon emplacements one after another. Entire lascannon batteries vanished in explosions as ammunition stores detonated.
At the same time, the turret-mounted Skyreaper Batteries opened fire.
Streams of high-caliber rounds swept across the battlements.
Traitor guardsmen were torn apart.
Others threw themselves behind cover.
Many never rose again.
Originally designed as anti-aircraft weapons, the modified Skyreaper Batteries proved just as deadly against infantry and light vehicles. Advanced auspex systems identified targets automatically while servitor-controlled targeting systems tracked and engaged enemies with ruthless efficiency.
The wall became a slaughterhouse.
Then the Mastodons reached the fortress itself.
Twenty-two Siege Melta Arrays fired almost simultaneously.
Blinding beams of molten energy struck the ancient walls.
Stone vaporized.
Adamantium melted.
Entire sections of reinforced battlements simply ceased to exist.
The fortress shook.
Cracks raced across the western wall.
As the cracks continue to spread, a massive sound of rumbles suddenly echoes through the air.
One of the Mastodon, transporting the Flesh Tearers Captain and his men have crash through the already heavily damage wall.
The moment the first Mastodon crossed into the fortress, its massive front assault hatch slammed open.
Red and black armored warriors stormed out.
The Flesh Tearers hit the defenders like a tidal wave.
Chainswords roared.
Bolt pistols barked.
Traitor guardsmen died by the dozens as the Flesh Tearers tore through their lines, painting the shattered ground with blood and broken bodies.
The breach widened with every passing second.
Seeing how weakened the wall had become, several Mastodons simply drove directly into it.
Ancient engines roared as thousands of tonnes of ceramite and adamantium smashed through damaged sections of the fortress.
Rockcrete exploded outward.
Defenders were crushed beneath collapsing debris.
Nearby Mastodons followed suit, creating new breaches rather than funneling through the original opening.
The entire western wall was beginning to fail.
With thunderous crashes, two more sections collapsed.
Now three massive breaches led directly into the fortress.
The wall could no longer contain the assault.
In the central breach, the Dark Knights emerged.
The assault hatch of the lead Mastodon opened and a hundred Cataphractii Terminators advanced through the smoke.
Storm bolters blazed continuously.
Mass-reactive rounds shredded traitor guardsmen and detonated weapon emplacements.
Behind them came the rest of the Dark Knights 1st Company.
Unlike the Cataphractii veterans, they wore finely crafted Artificer Armour.
Other than to increase their mobility in the urban region of the fortress, it also serve as a disguise.
Atharion have disguise the rest of the company as element from the 2nd, 3rd, 5th and 6th companies to make sure that them didn't find out about their blatant disregard of the Codex.
As the Dark Knights advanced through the central breach, the Executioners spearheaded the assault through the left flank.
The warriors of the Executioners lived up to their reputation.
Chainaxes rose and fell.
Power axes split armor and bone alike.
The defenders were driven backward by relentless aggression.
Where the Flesh Tearers resembled a raging wildfire consuming everything in its path, the Executioners fought like an executioner's blade—precise, brutal, and unstoppable.
Far ahead of the advancing Executioners, a traitor lascannon team abandoned its previous position and hurried to establish a new firing point overlooking the breach.
The crew barely managed to place the heavy weapon on its mount before death found them.
Accurate bolter fire tore through the team.
One traitor's chest exploded.
Another's head vanished in a spray of blood and bone.
The remaining crewmen were cut down before they could even reach cover.
Behind the advancing Executioners, a Black Guard battle-brother lowered his bolter and immediately began searching for another target.
Around him, five Black Guard squads had established supporting positions among the ruins and shattered fortifications.
Their role was simple.
Eliminate anything capable of threatening the assault.
Heavy weapon teams.
Officers.
Vox operators.
Anything that might slow the advance.
Every few seconds another disciplined volley rang out across the battlefield.
Every few seconds another enemy position fell silent.
The same scene was unfolding on the opposite flank.
The Flesh Tearers carved a bloody path through the fortress while Black Guard marksmen advanced behind them, providing covering fire and suppressing enemy strongpoints.
It was a strategy Atharion had deliberately arranged.
The Flesh Tearers and Executioners excelled in close-quarters combat.
Given the opportunity, both Chapters would happily throw themselves into the heart of the enemy.
The Black Guard ensured that enthusiasm did not become recklessness.
Whenever the traitors attempted to bring heavy weapons to bear, precise bolter fire eliminated them before they could fire a shot.
Whenever reinforcements appeared, the Black Guard pinned them down long enough for the assault forces to close the distance.
The combination was devastating.
Looking over the battlefield through the tactical display of his helmet, Atharion watched the assault unfold in real time.
Blue runes steadily advanced deeper into the fortress.
Red runes disappeared one after another.
The enemy's defensive network was collapsing.
"Advance," Atharion ordered.
Immediately, the central assault force surged forward.
Four Contemptor Dreadnoughts moved alongside the Dark Knights veterans, their ancient forms towering above the battle-brothers around them.
Twin-linked weapons thundered.
Power fists crushed bunkers.
Enemy firing positions vanished beneath overwhelming firepower.
Their destination was clear.
The central command tower.
The heart of the fortress.
The location from which the enemy coordinated the defense.
As Atharion advanced, another sound reached him from above.
The wet sound of blades cutting through flesh.
He looked toward the battlements.
The Raven Guard had not forgotten their mission.
While the majority of Effe's warriors continued sabotaging communications, ammunition stores, and command infrastructure, the Shadow Captain had detached an Assault Squad to support the attack.
Dark-armored figures moved through the defenders like wraiths.
Their Lightning Claw shimmer as the force fields on them being turn on.
Traitors who had abandoned their positions and sought shelter upon the walls found themselves hunted instead.
One by one they died.
Many never even saw their killers.
A Raven Guard would emerge from the shadows, strike, and vanish before the corpse hit the ground.
Panic spread through the remaining defenders.
Some attempted to flee.
Others fired wildly into the darkness.
None of it helped.
===
"Whats the status of the worlds?" Paladin Nexus, the commander of the Grey Knights Strike Force ask.
"It's bad," the Justicar replied grimly. "If we do not commence raids and destroy the altars, the worlds may be dragged into the Warp. Worse still, the corruption could grow strong enough for reality to break down completely, allowing Warp rifts to manifest across the system."
While Atharion continued his campaign at Voket, the Grey Knight strike force had already arrived in the Tri-Six System as promised, just two months late as they got side track with other daemonic incursion on their route.
The moment they entered the system, they launched a series of reconnaissance and containment missions across the three worlds, seeking to determine the true extent of the corruption.
In the end, combining the information they gain from Tadig and from their mission, the main source that contribute for the heavy Warp corruption are the twenty-one alters on the three worlds, seven alters on each of them are dedicated to worship of Nurgle with thousands of colonists on the worlds sacrifice on all those alters.
After several hours of analysis and discussion, the Grey Knights reached a unanimous conclusion.
The altars were acting as anchors, drawing Warp energy into the system and sustaining the corruption.
If all twenty-one altars could be destroyed, the ritual network connecting them would collapse.
The corruption would not disappear immediately, but its spread would be halted.
Given enough time, purification efforts could begin.
More importantly, the worlds themselves might still be saved.
Luckily, while Atharion unable to arrived in time, the others still able to arrive.
Atharion, knowing how the Grey Knights will deal with mortal that expose to the knowlegde of Chaos, have restrict all Auxilia to join in the Battle of Tri-Six and only allow the other Astarte Chapters and the titan Legios to participate.
The first to arrive were the Crimson Fists, followed by the Iron Champions and the Fire Hawks. Not long after, the Angels of Wrath entered the system as well, having finally completed their secret mission and returned to the crusade.
Alongside them came the Titan Legios.
The proud engines of Legio Solaria marched beside those of Legio Argentum Fulgur, their immense war machines transported across the void aboard Mechanicus vessels. Together they formed one of the largest concentrations of Titan strength assembled during the entire Camelarion Reclaim Crusade.
The Titan battlegroup Atharion had requested months earlier had finally completed its assembly.
Because of the information received, Nine decided to form a powerful battlegroup that not only can deal with the traitor Titans, but also able to, in theory, deal with the daemons.
The battlegroup consisted of two Warbringer Nemesis Titans, ten Warlord Titans, and twenty-five Reaver Titans.
Even by Mechanicus standards, it was a formidable concentration of firepower.
At its head marched the Princeps Maximus himself.
His command throne was housed within the Warmaster Titan Dies Vindicta.
Among the Titans that still stuck in the vault deep in Thoros, there are multiple Warmaster titans that already undergoes repair for a long time to bring them back to operational capabilities.
With large effort and large amount of resources continuously pour into the vault, the Magos Autokratoris within the vault have finally revive the five Warmasters, with one of them now will serve in its first battle.
Nexus, looking at the combine Astartes and Titans force that have arrived, begin to formulate a plan to at the very least, save the capital world of the system, where it have the largest potential and also where their main target, the Plaguecaster located at.
"We cannot wait for the Dark Knights," he said firmly. "We must strike now and end this before it is too late."
He turned toward the Justicar.
"Inform the Captains and the Princeps that we will hold a war council immediately."