The First Testament
The slightly reformatted original prompt reply
Doomslayer has entered Equestria through some contrived 4th dimensional warp-realm fuckery. This being of pure hatred and rage is totally, and utterly confused by the poners. He gets chummy with the mane six even though he is effectively mute. Offers Spike a brofist which forever seals their blood brotherhood.
Meets the princesses, who realize there's more to him than the girls thought. Conducts a secret meeting, where the Doomslayer, though gestures and the prophecy stones he managed to hide somewhere on his suit, explains what he is, what he has done and where he is from. The princesses are alarmed, but are confident he presents no threat to them.
Instead, they fear Hell may breach the Tartarian Gate. As if on queue, they get a letter from Spike, written in his words detailing horribly violent and cruel monsters that have come out of the Everfree. The Slayer's expression invisibly changes beneath his visor as a bassline slowly builds along with quietly distant guitars. He finally utters his first words:
"TAKE ME THERE."
The Doomslayer arrives back in Ponerville instantly, where he now stands above an Imp that is about to kill a pony. Rip and Tear begins to play. The imp doesn't stand a fucking chance as it is torn limb from limb. Other nearby imps find themselves being beaten with the previously removed limbs. The demonic incursion is abated as the music comes to a close.
Blood and gore thoroughly coat the town, and not a drop of it is pony blood. The mane six are initially horrified by the Slayer's tremendously cruel killing spree. He approaches them, clearly anxious, and speaks.
"Are you okay? Did they hurt you?"
The girls suddenly find comfort in the tall man's presence. Hours later, as the gore is cleaned in a delightfully dark musical...
The Doomslayer has a late lunch with his new friends, all happy and content with their new lives. The demons will come again, for sure, in greater numbers and strength. The ponies aren't worried, though.
The demons should be.
Some days later...
The better formatted continuation
The Slayer and his new friends are relaxing at the lake. He, despite still wearing the Praetor Suit, is sunbathing in Celestia's glorious light in a pool chair. For the first time in as long as he can remember, his hatred is sated. Eyes closed, he reflects on his journeys. After everything he's been through? Some cute talking horses playing in the water is like a healing salve on an aching burn.
Though none of the girls shall ever see it, he is smiling contentedly beneath that translucent visor.
"Slayer! There's a couple of Cacodemons heading for Ponyville, can you take care of them?" He hears Twilight call from across the crystal clear water. The Hellspawn have reduced their attacks to small, inefficient parties of no more than 10 demons. He cracks his eyes open to see them hovering slowly over the trees in the general direction of the poner town. Hefting his Rocket Launcher from beneath his chair, he lazily points the sights in their direction until a lock is confirmed on them.
He pulls the trigger, and a small cluster of rockets fly towards the now startled gas bags. Mere seconds later, they detonate in a shower of gore. Satisfied, he sets his trusty explosive device beneath his chair once again.
"Thank you!" Twilight calls out once again.
Fluttershy's pet rabbit, Angel, leaps up unseen into the Slayer's lap. He finds himself being gently stroked by the armored hand of his loving defender. Another smile creeps up on the Hellwalker's grizzled visage.
Actual STORY appears
They are rage.
Brutal.
Without mercy.
But you?
You will be worse.
Rip and tear...
Until it is done.
Twilight shoots up from her bed, wide awake in terror of her unholy nightmare. Panting and breathing heavily, she is divided on whether or not to focus on the memory of it, or to try and forget about it. Her inquisitive nature gets the best of her, and she focuses her innately sharp mind to capture the memory of those hellish images. What did that symbol mean? Was that the Doomslayer she saw?
Did he really....
What the hell did she just experience?
The Hellwalker, Terror of the Dark Realm, stands in the kitchen of Twilight's treebary, unarmored and unclothed save for some very comfortable boxers made for him by the lovely Rarity. Making himself a simple, but hearty breakfast, he has a full plate of eggs, toast, some waffles, and a couple of Pinky steaks. Turns out those Pinky demons make for good meat. The terror they experience before being butchered alive by the Slayer really gives the steak a rich flavor.
Crazy, right?
A warm, fatherly smile on his face, he sits down at the slightly-too-small-for-him table and quietly enjoys his home grown meal. He's the happiest he's ever been. The demonic incursions have all but ceased. They're getting harder and harder to find, fewer and fewer in number. Even Cerberus is doing better. Being killed by the demons and resurrecting himself later over and over again was starting to take a toll on the ever vigilant guardian of the Tartarian Gate.
Twilight sees the Slayer sitting comfortably at her table, enjoying a big meal he made himself. He's honestly kind of adorable, seeing him like this. But the dark whispers of her nightmare creep back up to her mind and is reminded of the current task. She needs to get a look at his armor more closely.
And he isn't wearing it. Good. Twilight needs to see that sigil again.... what could it mean?
As the Slayer continues to enjoy his meal, something bothers him. He remembers his past, piece by piece.
The things he's done.
His son.
The Betrayer.
The Seraphim.
The Sentinels...
The Knight Sentinels... he found himself longing for their brotherhood once again.
...
He fights back a tear as he remembers how they forgave him, after everything he'd done, after Argent D'nur had fallen to Hell's onslaught. He can clearly see all his brothers again. And he again can clearly see the twisted, evil visage of the Icon of Sin. The foul beast that his son's soul was used for. That he had to put down.
He pauses his meal, remembering in solemn silence. Images of his newfound friends appear. More and more, they overtake the images of his past... And become promises of his future.
Without anything holding him back, he returns to his meal with a renewed vigor. Not rushing, but in fact thoroughly enjoying the things this new world had to offer. What could go wrong?
Twilight stands in her basement, inches away from the currently idle Praetor suit. Her eyes are transfixed on the strange sigil on the helmet. She moves her hoof to brush against the arm̺̍̊̄͟ŏ̓ͤ̑r̨̟ͬ͋ s̴̵͕̹̤͚̍ͧ̃̋ͯ͂͢h̛̝̱̫̤̪̱̞͔̠̿͂ͯ̇ͣ͘e̵̴͇̩̟̾ͤ
In the first age, in the first battle, when the shadows first lengthened, one stood. Burned by the embers of Armageddon, his soul blistered by the fires of Hell and tainted beyond ascension, he chose the path of perpetual torment. In his ravenous hatred he found no peace; and with boiling blood he scoured the Umbral Plains seeking vengeance against the dark lords who had wronged him. He wore the crown of the Night Sentinels, and those that tasted the bite of his sword named him... the Doom Slayer.
The voice in her head finally quiets.
What the fuck?!
As she lay flat against the floor, struggling to breathe through her panic and fear, she remember the words. 'He chose the path of perpetual torment. In his ravenous hatred, he found no peace.'
..what could that mean? What did he do?
Twilight re-enters her room some few minutes later, having calmed down somewhat. She lay back in her bed, mind parsing through all the new information she has. The Slayer is clearly and obviously a warrior, she didn't need this little acid trip to tell you that.
But...some of what was said bothered her. It implied some unsettling things. And she bel-
"Ah, good, you're awake. Long night? You are normally awake quite early."
The Slayers roughly textured yet clear and deep voice reaches Twilight's ears from her doorway. He's taken to speaking more, now. Still a little unusual for him, after all those eons of silent rage. However, it's almost therapeutic, being able to voice his thoughts once again. However infrequently he chooses to do so.
"Come on down, Twilight. I'll make you some pancakes, just the way you like them."
That warm, fatherly smile graces his large and well sculpted face once again, simultaneously conveying a sense of comfort and safety, and a darker past within to Twilight. She'll get answers soon enough.
But she's getting pancakes right now.