CR: Hello everybody and welcome to this Doom fic called "Eternal Partner"!

Alex: Again? Didn't you say that you were going to focus on the other stories?

CR: And I did, but this fic isn't like the others. For, this fic is a collaboration type fic!

Alex: What? With whom?

CR: A friend of mine on Discord called "Oosername", he's the one that came up with this idea. We talked about it, and by the end of it, it was decided that we would both publish this story under this name. I would publish it here in fanfiction dot net, while he would do so in AO3.

Alex: Huh, this might be interesting.

CR: I hope it will. Also, brief disclaimer for y'all: This story contains several spoilers from the DOOM Eternal campaign, so if you haven't played it or haven't finished it, then I suggest that you do so first. And while I would like to mention that this would have gore... this is DOOM, let's not kid ourselves.

Also, here's the link to my server if you're interested in joining it: .4vCAydn

As well as the link to Ooser's profile on AO3: archiveofourown dot org slash users slash Oosername slash pseuds slash Oosername

Anyways...

On With The Show

The Slayer gave a hefty tug at the endoskeleton of his former ally in the small, glassless tube, letting it fall to the ground with a loud metal thunk before picking the shell of Dr. Hayden up by his arm.

"His life signal is barely readable" VEGA chimed in with an informative tone,but the Slayer swore he heard a tinge of concern in the AI's tone.

He honestly did not care for the traitor, his only concern was to find the last Hell Priest and only Hayden knew where he was; were it not for that, he would've left the machine to rot.

But alas, there were currently more pressing matters at hand, like the alarms that suddenly blared as the scientists around him started fleeing.

"WARNING: Demonic presence threat level 5 entering Main Laboratory" Was what came from the speakers as a hellish crimson portal was summoned a few meters to his west, a soft few soft demonic noises evident as an entity stepped out of the red portal.

He was… intrigued, to say the least.

"Opening the portal now" VEGA began, and the Slayer threw the barely living corpse of Samuel Hayden into the blue portal without looking, it making a loud but silent closing whoosh. His eyes were set on the figure that emerged from the other portal, watching as it slowly walked down towards him, its steps echoing loudly through the room.

"You were never one of us…" The entity, obviously a demon, began. The Slayer studied his opponent's body for a moment while it monologued.

Or rather, she.

"You were nothing but a usurper… A false idol" She spoke in a rough, lethal tone that carried a certain air of femininity. Her body both admittedly attractive and intimidating as her heap of undoubted muscle (covered in armour not too far from his own in appearance) led her around the room, carrying a large metallic scepter around, pretending to be struggling at moving it around as it followed the demon like the tail of a pinky.

"My eyes have been opened" She continued. But the beauty was more than obvious. Behind that plate of armour on her chest were a pair of F-cupped breasts that her muscles were holding like champions, and alongside those were thighs he would overhear his underlings say "they could crush a watermelon"... And, he could honestly see the appeal. Even her face, demonic in appearance toting with horns and all, had a beauty in some manifest form.

"Let me help you to see, Slayer" But alas, she was an enemy. And he refused to die here. Earth was still in peril, still a key target of the Khan Maykr's ploys.

The scepter roared to life with a single gesture, turning into an Argent Energy fueled Battle Axe as the brawl promptly commenced.

The Slayer immediately went for his shotgun, blasting a sticky bomb onto the Marauder with hesitation dead, watching as the hunter didn't even stagger at the blast, lunging close to the Slayer and slashing his torso, causing a cut across the front. This caused the Slayer to dash away and switch his current weapon for his trusted "steel barreled sword of vengeance" - the Super Shotgun.

Loading two shells rapidly into it, the demoness went in to strike with a wild swing, but she was caught off guard when the Slayer promptly pulled the trigger, the shrapnel tearing a bit through her flesh and the shock causing her to falter. He quickly capitalized on the opening by quickly delivering a Blood Punch that sent her back a few feet, the impact being more than enough to damage her.

"Gruhgh!" She grunted, and in retaliation, she sent a wave of Argent Energy at him through her axe, although he managed to dodge in time. Thinking quickly, the Slayer brought out his new Chaingun in Turret Mode and tried to fill her with lead, but the demoness brought out a shield that reflected all of the bullets, effectively making him waste his resources. When it stalled, the Slayer thought that perhaps what he needed to do was to overload it, so he brought out his Plasma Rifle.

It did not work either.

This also costed him dearly, for the demoness took the opportunity to dash near him and brought out a Super Shotgun like his own (minus the Meat Hook) and shot him at point blank.

"Argh!" The Slayer grunted from the shrapnel hitting his armor, but he did not falter and as she went for another swing, he struck again with the Super Shotgun, this time tearing parts of her flesh, revealing the raw meat that pulsed and bled. Knowing now that nothing else would work, he quickly reloaded it and shot her again, just a few seconds before she dashed away and sent another Argent wave at him. This time it was much faster, so it hit him once again, which reduced his armor levels to zero; now he ran the risk of losing health unless he did something to defeat her and he was running out of shells.

Fortunately, a few fodder demons appeared in the form of Imps and Soldiers, so with a grin on his face (which could not be seen due to the helmet) he quickly approached one of the soldiers and brought out his personal Harvester: The Chainsaw.

His grin widened as the sound of the soldier's panicked growls and of the chainsaw tearing through him like butter rang through his ears, but he quickly put his head back in the game as he picked up the shells, bullets and plasma cells that dropped out of the dead Soldier's body and quickly dashed away from another wave of Argent Energy.

However, he flinched as he felt one of the Imps hit him with a fireball, which also irritated him, so, having already gathered enough energy, he approached the remaining fodder and let out a Blood Punch that blew them all away. With the distraction gone, he could now focus on the demoness.

The second he turned to look at her, she charged at him with another wild swing of her axe, but with lightning fast reflexes, he pulled the trigger on the Super Shotgun, tearing chunks of her flesh apart once again, and shot her again while he had the chance. But he was surprised when she immediately charged at him again, but he could not dodge in time; the demoness managed to leave a quite nasty gash on his suit, which now that he realized, it had also grazed his skin beneath.

"Gruhgh!" He grunted, and he let out another grunt as the demoness used the momentum to deliver another nasty gash, followed by a volley of shrapnel from her Super Shotgun. The Slayer idly noted that his health bar was near the 100's, nearly half of his health was gone by this point.

He narrowly dashed away from another swing, which also ruined her tempo, so he tried to shoot her again, but unlike the other times, she was ready for it; quickly bringing out her shield, she managed to block it in time and was prepared to attack again.

But the way she did, was what actually surprised the Slayer.

She put her hand to her mouth and whistled, but just as she did that, a yellow, spectral wolf, not unlike the green wolf spectres that he had seen in Exultia, appeared at her side and quickly charged at him.

During that brief period of time, the Slayer realized that this demoness was a Night Sentinel at one point or another.

Now understanding the origin of her resilience, the Slayer put all of his focus this time on her, but quickly shot at the wolf when he sensed it near him, but the creature was nimble enough to dodge it and it managed to bite his leg, making him grunt once again. This also had the unfortunate effect of taking his focus away from his enemy, which costed him dearly as she capitalized on his distraction and swung at him.

"Grhgh!" He grunted and hastily dashed away. He panted as his wounds were dragging him down, he could feel his heartbeat ringing through his ears and his H.U.D flashing red as his Health bar was on the 30's. One more hit and he would be done for.

Now knowing just how dangerous the demoness was, he put his focus on the wolf first. When he sensed it approaching, he quickly brought out his Heavy Cannon with the Sniper Lens, so he aimed at it with such precision that he managed to shoot it right in the head, which also dropped out some armor plates.

Quickly dashing, his suit idly picked up the plates and managed to slightly restore his armor and seal his wounds a bit, just in time as the demoness charged in for another wild swing, but this time he let out another volley of shrapnel at her, and this time it caused her to stagger.

With that in mind, he went in for the kill, literally.

Quickly approaching her, he punched her in the face, which caused her to stumble and drop her battle axe, which he quickly picked up and swung at her just as she turned to look, the blade cutting through her neck and severing her head from her shoulders, effectively killing the demoness. Now that the fight ended, the Slayer threw the battle axe away and sighed quietly as he could feel his suit absorbing his fallen enemy's Argent Energy and supplying it to his system, effectively healing him a bit.

"It is good to see that you managed to defeat the demoness, but as you two fought, I managed to find some information about her in the UAC archives. Do you want to hear it?" VEGA spoke to him after a few moments, and the Slayer gave a nearly imperceptible nod to the AI's query, to which the Slayer then found some texts appear on his H.U.D and a few pictures of the demoness he fought.

"Apparently, this demoness is known as 'The Marauder', the archives here tell that she was at one point a Night Sentinel that had joined the side of the Maykrs during the Sentinel Civil Wars. Here it also says that she had fought alongside the Slayer himself in the fight of Taras Nabad, as well as many other battles alongside the Slayer" VEGA informed him, to which the Slayer only nodded.

There were few things that he remembered from his past with the Night Sentinels, but he did not remember the exact identity of some of them; it isn't that he does not think that they're worth mentioning, no, he held a deep respect for the Night Sentinels that took their time to teach him their ways, their language, their traditions, their discipline.

He was also honored by the Sentinels that following him in his Unholy Crusade through Hell which, while now they were to stop the demons, it was at first to kill the demons that had murdered his pet rabbit, Daisy. That is… something that he's not very proud of, but it was because of that that he now had the chance to do the right thing.

"However, it is also mentioned that she had at one point or another belonged to a special force unit of the Night Sentinels called 'The Marauders', followers of the Slayer's ideology of ripping and tearing apart his enemies. Wild and savage, they followed through with that ideology, but they were loyal only to the Slayer, not King Novik, nor the Maykrs.

But, during the Sentinel Civil Wars, this particular Marauder had very conflicted feelings about whom she should serve. In the end, she chose the Maykrs, and was forced to kill her former brethren by the Maykr's command until she fell in battle" VEGA continued, to which the Slayer only nodded. He heard of 'The Marauders', they were his own Task Force at one point, but then as he left to Hell in his Crusade, he knew no more about what happened to Argent D'Nur; he was not surprised to see that one of them joined the Maykrs, many seemed to do the same nowadays.

"But as she died, she did not have the peaceful afterlife that she believed she would have once she perished, instead the Khan Mayrk took her soul and infused it with Argent Energy to turn her into a demon, then bestowed upon her speed and strength, gave her a specialized armor, as well as a Super Shotgun, an Argent Axe and a Shield, all of that with one purpose: To hunt the Slayer" VEGA finished the entry, and the Slayer then understood why she was such a formidable enemy.

Not even the Doom Hunters that he had faced in the UAC Cultist Base pushed him as much as this demoness, only the likes of the Spider Mastermind managed to do so, and even then, it wasn't as close as this. Another thing that intrigued him was that she was the only female demon (aside from the Whiplash) that he had ever encountered in his life. All demons were either beast like (Ex: Cacodemon or Pinky) or if they were humanoid they would seem like males (Ex.: Hell Knight, Mancubus, Carcass).

Regardless, he already wasted enough time. Without even saying a word, VEGA opened the portal for the Slayer to walk into. But what he didn't know, was that it was just the beginning.

Darkness.

It was all that she could see, but that did not matter, for, all that she could remember, was the enemy that had killed her.

The Doom Slayer.

Such ferocity that he had as they fought, such precision that he possessed as he easily banished her partner with a single shot, such savagery that he had as he tore through his enemies like butter. Nobody had ever given her such a fight.

Not even the heretics that she had at one point called 'Brothers and Sisters' had managed to defeat her; her death was caused by her own wounds, but it was only after her enemies had fallen.

The Slayer had countered all of her moves, he had such resilience that it was almost as if the legends of his might were actually undermining him.

Her attacks could cleave through armies, and yet he managed to withstand them, and even her partner's jaws, which were strong enough to dismember someone, were not strong enough to tear him apart.

No, instead, the Slayer ripped her apart, tore her flesh with his cannons of DOOM. Such power, such resilience… it was… it was…

Entrancing.

Then, the Marauder's eyes opened to the familiar orange stormy skies of Hell, where she had finally emerged from the sarcophagus that had reformed her body.

Her footsteps were loud, her clawed feet leaving Mark's across the floor as her tall, pale nude body was visible for any other demon to behold, but at her current location, nobody could.

As she then witnessed how her suit had reformed in another sarcophagus, similar to her own, she reminisced about the Slayer. Her body briefly pulsed as she thought about him, until a savage grin formed on her face.

Oh, she knew they would meet again, and when they did, she would make him see…

"You cannot resist the will of the Khan Maykr"