Warning: I know very little about Warhammer 40k. So if something is wrong, please tell me, but remember that this is a fanfiction and I like to change things.
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Valerian, the Primarch of the III C-Legion disembarked the Armed Freighter that led him and roughly 500 of his brothers to Mars. The legions were now called differently. The C-Legions were the Custodes Legions. Legions are made entirely out of Custodes right now, but later, they will be formed by his sons. The God Emperor has blessed him to become something different from a regular Adeptus Custodes. He was now a Primarch Custodes, a weapon forged for the Emperor's will and one that would never fail him, not while he still drew breath.
[Picture]
The scouting group of Imperial Guards that was sent out to Mars has not called back, which was unnerving. The Astra Militarum, also known as the Imperial Guard, is supposed to be the largest coherent fighting force in the Universe at some point and serves as the Imperium of Man's primary military force and the first line of defence from the myriad threats which might endanger the existence of the Human race. The God Emperor decided to keep the name humans for their race as, sooner or later, the Earth or Terra, as he would call it, would be united under the Aquila.
There weren't many members in the Astra Militarum at the moment since the Phalanx had to be manned and controlled now that there was a serious lack of sufficient manpower. Valerian was dispatched to have a look and evaluate the threat that most likely took out the members of the Astra Militarum that scouted Mars. And, if necessary, take care of the threat and report it. The Emperor was looking for resources of all kinds, so if the threat was useful to him in some way, they would gladly bring it to him.
The Custodes began to spread out slightly to cover more ground. Their helmets sent them information about the terrain, and what they gathered was concerning. There was a high concentration of psychic energy in the air and heat stemming from fires as well. The ground was scorched and painted with battles. He might have appeared through the power of the Emperor, but he had been gifted some memories of the Emperor and pushed to thousands of years of experience in the matter of seconds. The Custodes are different beasts compared to the Astartes; they aren't bothered by the heat and radiation in the air. But what are the high levels of energy in the air? That's a concern.
"Some form of a battle has taken place here," one of Valerian's men says as they observe the wreckage.
Everything was constantly on fire, and large amounts of destruction could be seen. It was peculiar, and the high levels of psychic energy were telling Valerian that they were going to face unfriendly opposition. But it wasn't a problem; they would deal with the aliens.
"Not a battle, a war," Valerian corrects.
The Primarch Custodes looks around a moment longer and then gives out his command.
"Send out the Vertus Praetors and give me eyes in the air."
"Yes, Primarch."
These airborne warriors serve as the eyes and ears of their Shield Companies, soaring over the battlefield and voxing word of the enemy's movements. Their auto-senses are optimised for this duty, featuring suites of data-augurs, optical auspicators, and multi-spectral motion-oracles that enable them to detect and track even hidden foes. With a squadron of sharp-eyed Vertus Praetors circling above, a Shield-Captain can rest assured that the enemy stands little chance of catching him unawares. At least usually.
*BOOOM*
Before reality had set in fully, the Shield-Captain to Valerian's right moved his body. Monstrous force hits his right shoulder and disintegrates it, without leaving anything behind. If he hadn't moved before, the Shield-Captain would be dead right now. The alarm is rung and the Sentinel Guard take up defensive formation wanting to protect their Primarch. They look to the front and see an alien floating just above the surface.
[Picture]
A Burning Martian.
The Custodes attack. Like a well-oiled machine, they aim their Guardian Spears forward, firing their Bolt Casters at the Martian. In the Custodes' skilled hands, Bolt Casters are able to lay down a hail of fire at short range that can cut down the enemy of the Emperor, but this time, things are different. Bolt weapons fire caseless self-propelled mass-reactive shells known as bolts at hypersonic velocities, which are timed to explode just after penetration for maximum lethality.
*BOOOM*
"RAAAAHHHH!" the Burning Martian roars defiantly as the shells hit him. But to everyone's surprise, there is no damage to be seen.
Then, he moves. Before they can blink, the Burning Martian appears before several Custodes and swipes his large hand diagonally, using his monstrous physical prowess to telekinetically cut through the Auramite armour. Several Custodes are split apart with one swing. But that's not all. The powerful faction takes this information and adapts to it. Those who were just cut open use the last of their strength to move forward, instead of just falling to the ground. The Burning Martian sees these weak creatures push forward and try to grab him in the moments of their deaths. He uses a powerful telekinetic push to shoot them away from him before they touch him.
However, the next line has already arrived, without him noticing. Custodians constantly have to protect the Imperial Palace, a vast sprawling complex the size of a country, making them as much intelligence agents and spies as warriors. They swing their Guardian Spears from different angles, trying to reach the alien, but are again blocked by the telekinetic might of the Burning Martian. A powerful flame hits their bodies. Their Auramite armour resists momentarily, again, surprising the Burning Martian.
*BOOOM BOOOOM*
More attacks hit him from the sides and from above. He uses the Custodes as projectiles and crashes them into the approaching ones. Those who rush forward, dodge and speed up further, angering the Burning One. He finds the attacks of those lowly creatures to be an affront and uses his mighty telepathic prowess to create an illusion. But the Custodes have an immensely high resistance to telepathy and heat, which is helpful against the Burning Martian. Still, they are not nearly strong enough to compete in the physical arena.
The Burning Martian grows angry and attacks the Custodes with his most potent telepathic assault. It works, somewhat and even slows the approaching Custodes down. He pulls them towards him and grabs their helmets, crushing their armour and heads with his monstrous strength. At that moment, several Vertus Praetors arrive, shooting forward and aiming their Jetbikes at him. They jump off, let their bikes crash into the alien, and then swing their Interceptor Lances towards him.
The Burning Martian is unbothered about the crash and raises his hands, trying to catch their lances. But that's a mistake. Power weapons disrupt the bonds of matter by surrounding themselves in an energy field, of which the Custodes possess some of the most potent examples. Durability doesn't matter in this case. The Vertus Praetors' Interceptor Lances cut cleanly through the Burning Martians' hands, severing them from his body and surprising the alien creature. Feeling their danger, he pushes himself through the air, flying backwards, just before the Custodes can attack him again. But that's another mistake, as Valerian has already coordinated their attack perfectly. A Sentinel Guard wait for the Burning Martian.
Seeing himself caught, he shoots towards them despite being able to fly into the air. His hand has regenerated again, thanks to his potent regenerative factor. He uses all of his strength and punches forward. His fist crashes through the first Sentinel Guard's powerful Praesidium Shield and even moves through the entire Custodian, coming out on the other side. But he doesn't manage to pierce another Custodes. They swing their Sentinel Blades in a powerful arc, cutting the Burning Martian the second time today.
The alien's right arm falls to the ground, and a deep gash appears on his torso. Before more of the power swords can hurt him, the Burning Martian sends out a psychic power wave, pushing everyone away from him. Usually, such an attack would disrupt the atomic bonds, but they were touched by the Emperor's grace, giving them high resistance against such attacks. The alien uses a higher speed than he did during the entire fight, and also more strength. His fist punches through the Custodes' Auramite armour and bodies, killing them by the dozens.
.
Despite the carnage that is happening right now, the psychotic warmongering Martian is not enjoying this. Burning Martians can feed on feelings like sorrow, desperation and suffering to reproduce asexually and give them pleasure during a battle. But all the alien feels right now, from the Custodes, is confidence and deep faith in their ability to win. They can't lose, they shall not lose, for losing would mean failing their Emperor, and that's unacceptable.
*BOOM*
A power gauntlet hits the Martian in the face. Valerian has arrived. Seeing the larger stature compared to the other Custodian, the Burning Martian focuses on the Primarch Custodes, just as intended. With a powerful psychic roar, the alien attacks. The speed surpasses even the immensely enhanced senses of the Primarch Custodes. His mighty fist approaches Valorian's face. However, in the last possible moment, the fist is moved to the side, missing Valorian's face narrowly. The Martian is once again surprised. This is impossible. Valorian's fist hits his body and a power knife plunges into the Burning One's skull from the right side.
But he's still not dead.
"RAAAAHHH!"
He turns around, swinging his arm around, attempting to crush Valorian again, but he misses, yet again. The reason for this is rather 'simple'. Valorian ducks underneath the swing and pierces his heavy power sword into the Burning Martian's chest, as deep as it goes. He pierces the alien's heart and makes him feel tremendous pain. Pulling his sword out again, Valerian swings it horizontally and decapitates the Burning Martian, finally killing him.
However, he is granted no reprieve. Reaching into the numerology of the near future and following his insane instincts, he predicts an attack coming from behind and dodges to the side.
*BAMM*
He looks forward and sees it—a horde of Burning Martians has arrived, attracted by the battle. All this time, they had just fought one Burning Martian, and the fact that they even managed to kill him is already a miracle. In truth, the only reason, why they managed to accomplish this, against a foe that is on par or even above Superman in power, is that the Custodians are touched by a spark of the Emperor's own power, which manifests as a supernatural warding, making it so that bullets and bolts are turned aside at the last moment, blades fail to strike home, and even the psychic powers of the foe can suddenly and inexplicably flicker away to nothing. And yet, here they are.
The first Burning Martian charges forward, shooting through the air and towards Valerian.
*BRRROOOOOOMM*
A loud and powerful explosion announces the arrival of another power. In the back, a Custodian in Aquilon Pattern Terminator Armour has arrived. He just fired his twin-linked Adrathic Destructors at the Burning Martian.
[Picture]
Adrathic Weapons are a type of disintegration weapon, relics of the Dark Age of Technology. They use a potent but dangerously unstable energy beam to sever the internal bonds of matter, causing objects caught in their path to unravel in a spectacularly destructive manner, leaving only a flaring after-image of what was. And it just hit the Burning Martian. As the dust clears, the gruesome image shows just how powerful the weapon is, as the Burning Martian's body was just unravelled, killing him.
The remaining few Custodians are already back in formation and prepared to die on this battlefield. But they must inform their Emperor of what is going on.
.
In a special room of the Phalanx, Neoth is busy creating something which will not only help the Imperium reach new heights, but it will also push him beyond untold limits. He has been working on a way to use his strength and focus on that for now. He will remove all his weaknesses and, as a Greek Deity, that would be the need for faith. But he is different, thankfully. While he can grow stronger through it, he isn't dependent on that.
Right now, Neoth is working on technology and his psychic power. It is already immense and has limitless potential, but there is always more to be had. As it happens, the DC Multiverse has something perfect for him and his Imperium: The Sage Force.
*Beep beep beep*
"Yes?"
[Your Excellency. We have encountered a new breed of aliens on Mars. They use pyrokinesis and have immense psychic powers. I'm most sorry, but we won't ma-]
A portal opens before Neoth, and he steps through it before Valorian can finish the word. He arrives on the battlefield of Mars and sees the devastation caused by their fight.
"-ke it," Valorian finishes his sentence.
The Primarch Custodian has half of his face missing, but he just ploughs on. His powerful arm swings the Guardian Spear, which he picked up from the ground, cutting through another Martian. Then he finally realises that the Emperor has arrived.
"Your Excellency. You're here."
Neoth feels the powerful Burning Martians and their collective psychic prowess. He sees them all shoot through the Martian air. Time suddenly slows down tremendously.
[00:00'00''00'''00''''00'''''00....]
The Emperor's Sword appears in his hand. Touched by his psychic might, this finely wrought, master-crafted blade is lit from hilt to tip with leaping flames. Neoth swings it through the air horizontally. As it is swung, the burning blade draws a pyrotechnic arc through the air. It looks as though the arc has stopped in time, but if one were to see closely, one could see that it wasn't even there anymore and had long passed through the air.
Then, time resumes.
*SHING*
...
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I would like to ask those who don't know to read about both the Custodes and the Burning Martians. There is no chance that the Custodes were going to win here—none whatsoever. I like them a lot, but I can pull only so much BS (which I did through fate manipulation).
I will show how much stronger or better they are than their Warhammer 40k counterparts later on. I hope you liked this.