Chapter One

Strange meeting

The young girl, barely in her teenage years, flew herself at the pile of metal debris even as bullets and flame flew around her. Her blond hair was dirtied with soot and smoke, as was her white and blue clergy outfit. Her vision was blurry and she vaguely heard someone shouting over all the fighting and destruction around her, calling her to flee. She would flee eventually for she had no wish to remain in this Emperor forsaken place any longer, but she would not do so alone.

Digging up the pile of metal was no easy task. Many pieces were sharp and the young girl had several cuts on her hand for her effort.

"Sister, can you hear me?" she begged. "Sister Superior, are you alright?"

The girl was elated when she finally found the hand belonging to the one trapped under the debris. She wasted no time pulling her out. The Sister Superior was clad in carapace armor which allowed her to avoid most of the harm from having a bunch of metal objects of different shapes and sizes falling upon her, but not all of them. A thin metal pipe had pierced her in the chest. Despite the lack of leg injuries, it was clear that she would not be able to move on her own.

"Leave me," said Sister Superior weakly. Her carefully braided brown hair was a complete mess and she could only open one of her eyes due to a trail of blood dripping from the top of her head. She coughed out more blood as she struggled to speak. "I will only slow you down. I am done for, but you can be saved."

"Don't say that," the blond-haired girl replied, exasperated. Though they had not been particularly close to each other, she could not leave anyone behind and not feel guilty about it. After all, it was her sacred duty to maintain the health and combat readiness of her sisters in arms – failing to do so was failing the Emperor himself. "We'll get out together. Just keep up."

"It is my fault that we end up… like this," explained Sister Superior. "I have failed you and our sisters. Let me join the Emperor's side – only He could forgive my mistake."

Ignoring her commander's plea, the blond-haired girl hoisted the other girl's arm onto her shoulders and dragged her out one step at a time. The Sister Superior protested verbally but not physically for her body had gone numb from the pain. The blond-haired girl did not look back. She perfectly knew doing so could warn her of the impending danger, potentially saving the lives of her and the woman she was carrying – she couldn't look back and find out what fate had befallen her comrades.

There used to be four.

Now there were two. One was definitely dead, another probably also dead. Not to say the chance of survival of the blond cleric and her wounded comrade was particularly high.

So how did it get to this?

Just an hour ago, the four of them were contemplating returning to the monastery after a day of patrolling in the area surrounding the convent they lived in. The group included a Flamer-wielding Sister, a Repentia, the leading Sister Superior and the girl herself, a Hospitaller in charge of healing and prayers. Six Orks were found on three separate incidents and taken care of quickly. The aliens were tough, as to be expected, but not very bright, and they died as well as anything that lost their head or had their midsection torn in half. The Adeptus Sororitas initiates followed the meticulously prepared instruction by the Convent Mistress and things went about as smoothly as it could have and no member was injured in the process, at least at first.

The sun was almost set and they were all tired, yet satisfied with the work done for the day, so Flamer-wielding Sister had suggested they should be heading back earlier for bathing and hot food. Sister Superior had rejected the idea and insisted on continuing the sweep, stating that Gretchins had been reported to have stolen food and electrical items from nearby farms and were holding up inside the wreckage of a Gargant. After debate, the rest of the team acquiesced to their leader's order despite knowing they were not prepared to make battle within such confined and utterly alien environment in the belly of a giant war machine built by the Orks.

Flamer-wielding Sister had initially argued that the Gargant had yet to be completely demolished or scuttled two months after meeting its demise for a reason and that the Adventure Guild appeared to have had taken interest in it so that a team of Adventurers would come eventually to deal with this. Sister Superior also dismissed any assistance from the so-called Adventurers. The local forces of the Adeptus Sororitas welcomed any who fought in defense of this planet but mistrusted those who considered money more important than the Emperor himself. According to Sister Superior, this piece of land comprising two rivers and one small town belonged to the Ecclesiarchy; it was their duty to protect it, not outsiders'.

Hospitaller didn't take part in the discussion and merely followed decisions made by her more experienced and combat-hardened sisters. Though she knew this was a bad idea, she went with it in the end. Repentia accepted it either way – she had already embraced martyrdom when she accepted her current position.

The Ork Titan was as marvelous as it was horrific. It resembled a gigantic version of a construction toy made by a child than anything that was constructed with a blueprint and a purpose in mind. In its death, the thing loomed over the valley like a small mountain; the multitude of guns and spikes protruding from it could be mistaken for trees from afar.

Hospitaller wasn't exactly sure how they got to this place inside the Gargant. She remembered entering through a massive hole on its side. The blackened metal suggested a cannon shell had hit the Gargant in the loading compartments to one or several of its guns, causing a catastrophic explosion that likely crippled it. Blood splatters on the floor, walls, and ceiling indicated someone was alive there when the hit happened but probably not afterward.

The group had moved in single file through the clogged corridor surrounded by strange alien pieces of machinery which Sister Superior warned not to pay any heed to. Repentia had taken the lead, followed by Sister Superior who carried a lantern with her, then Hospitaller and Flamer-wielding Sister covered the rear. The air was extremely thick with oil and metal, almost unbearable, but they marched on. Hospitaller couldn't recall which direction they took once they were inside. Was it left and left or left and right? The whole place felt like a maze and the directional signs were Orkish and indiscernible.

Flamer-wielding Sister had been twitchy and no doubt had been about to claim the whole venture into this place fruitless and insist that they should get out of there when the first Gretchins had shown up. Like the Orks, these creatures were green-skinned, but the similarity ended there. The Gretchins were the size of a human child and had scrawny features with long limbs and sharp ears and nose, whereas most Orks were burly with muscles. Any Ork's decision to encounter hostile would be to fight back, but the Gretchins had turned tails and fled when running into the Sisters of Battle. Despite their build which suggested a level of agility, the tiny Xenos were as slow and clumsy with their surroundings as their five-hundred-pound masters. The first skirmish had gone well.

But the advantage didn't last. Galvanized by the initial victory and slaughter of the foe, the Sisters of Battle had pressed onward deeper into the belly of the beast, and that was where the ambush was sprung. The floor beneath them had collapsed, causing the four to tumble down two levels below and into an open ground which apparently was used as gathering ground for the garrisoning Orks – more than just the ultimate tool of destruction, the Gargant was also a massive transport capable of bringing an entire army into the thick of battle. There, the Gretchins had been waiting and attacked in force. There were dozens of them. Their weapons were crude even by Ork standards, but sheer number made up for the lack of efficiency.

Flamer-wielding Sister had been the first to die. Several Gretchins had gotten the drop on her and stabbed her with their small knives, inflicting small wounds in multiple places which became severe when together. Unable to fight them off, the girl gave out a last prayer before detonating her weapon, taking the lives of her own as well as all of her assailants in a blazing fireball. Hospitaller remembered herself screaming in distraught like never before at the sight.

Realizing their folly, the rest of the Sisters had taken cover while finding a way out. Soon enough, the Gretchins were upon them, coming from all directions bearing crude firearms and close combat weapons and the depraved, shrilly laughter of predators coming for their hapless prey. Sister Superior and Repentia had fought them off with Power Sword and Eviscerator, respectively, while Hospitaller, not used to combat just yet, had knelt and prayed for deliverance. Sister Superior had been shouting the order to fall back when a green beam had been fired from the Gretchins' direction struck the wall behind her. The metalwork had contorted like a folded piece of paper before coming apart violently, burying Sister Superior underneath.

The last thing Hospitaller could recall before the current event was Repentia bellowing as she dived headlong into the large group of enemies, her two-handed weapon cleaving great arcs through them. Though part of her didn't want to abandon her friend and comrade to her fate, she knew there was nothing she could have done and saving Sister Superior was both possible and more important.

Much to her relief, Hospitaller finally managed to support Sister Superior out of open space and into a narrow path. Here, the confined space should prevent the Gretchins from either launching a surprise attack or overwhelm with greater numbers. This was far from escape, however. As the light of the lantern got dimmer, so was Hospitaller's hope. She did not know where to go to get out. Even if they had not fallen when the floor collapsed, the eerie corridors and pathways were indistinguishable from one another. There was no way of communicating for backup either; Flamer-wielding Sister had been the one carrying vox equipment, not that any force deployed from the convent would be able to get here in time except to exact retribution.

Exhausted, hungry, frightened, lonely and still feeling the pain from the drop, Hospitaller grew more desperate as seconds passed. She wobbled from side to side, feeling the weight dragging her down as the wounded Sister Superior couldn't keep herself up much longer. She could hear the leering voices of the Xenos at her back but could not bear herself to turn around to look.

"Just get the hell out," Sister Superior reinstated. "You… won't be able to outrun them with me along. I am just dead meat. Save yourself. Emperor protects you."

Before Hospitaller could reply, she felt an impact at her left arm just below the shoulder, followed by a sharp soreness. She whimpered and croaked, not having the strength to yelp, as a flow warm liquid ran down her arm. The shot came from a weapon of archaic design, solid slug; though it didn't go through the bones and she could still feel the use of her left arm, a chunk of flesh had been torn out and blood was oozing. The pain was excruciating, far more than what she had experienced during penitent rituals traditional to the Adeptus Sororitas. Both her and Sister Superior fell to the floor as the Gretchins caught up to them.

"Protection!" Hospitaller shouted and an energy barrier appeared between her and her pursuers. An overly eager Gretchin crashed into the shield and broke himself. The rest halted and began to pour fire into the force field even as Hospitaller desperately attempted to get up along with the now limp Sister Superior. "Emperor, please help us."

Her plea was answered as the Gretchins suddenly stopped attacking the weakened barrier. Though Hospitaller couldn't read alien faces, they seem to bear expressions resembling surprise and shock as they stared at the direction behind the two girls. Looking back, Hospitaller couldn't see anything beyond the proximity of her lantern but could make out a dot single of red light in the distance along the corridor. It was hovering, getting brighter, getting closer. A silhouette appeared, a large figure walked down the hallway, covered from head to toe in heavy armor, its footsteps resolute and brimming with intimidation.

From the shadow came a Space Marine clad in greyish Power Armor, an optic visor attached to the left eye of his helmet glowing crimson.

Their tiny brains finally working out which one was the greater threat, the Gretchins went around the power field and charged at the newly arrived Astartes. In quick motions, the Space Marines pulled out a shotgun and opened fire. The organization, combat doctrines and culture of the Space Marines remained much of a mystery to Hospitaller, yet she found it unusual that one of the finest warriors of the Imperium would be using such a low-tier weapon. The shotgun was of local design, not even Mechanicus-manufactured, ancient and almost as crude as the weapons employed by the Orks. Nevertheless, it proved surprisingly effective against clumped up enemies in enclosed space as each scattered shot reduced entire mobs of unarmored Gretchins to bloody mists.

Realizing they could not win, the Gretchins decided to cut their loss and fled just as they had when they were driven back by the Sisters of Battle earlier. The Space Marines stepped forward deliberately, pumping and firing his shotgun as he went. All but one of the Gretchins escaped. As it ran out of the shotgun's effective range, the Space Marine picked up a metal rod and threw it like a javelin. The rod hit the Gretchin at the back of its head and impaled it through the mouth.

With the area secured, the Space Marine approached the two wounded Sisters of Battle. Hospitaller tried to speak but her throat was dried and she felt sick and she coughed uncontrollably. The Space Marine produced a gallon of water and she took a big swig out of it, almost choking herself in the process. She then gave some water to Sister Superior who could barely stay conscious.

"Sir, you have our eternal gratitude," said Hospitaller, at last, clutching the wound on her arm. "Our fate would have been sealed had you not arrived. We are in your debt."

"Don't mention it," said the Space Marine. "You are not adventurers around here. Are you from the convent?"

"Yes, we are, sir," Hospitaller replied as she utilized the relative safety to stabilize herself and her comrade. Though her wound probably required more attention than this, Hospitaller simply washed it lightly before applying bandages. Her comrade's treatment was more pressing.

The metal pipe stuck into Sister Superior's chest probably didn't hit any vital organ, thank the Emperor, but she was losing a lot of blood and her pale face was an indication of that. Pulling the pipe out may lead to rupture which could be fatal, so Hospitaller did her best to stem the bleeding by disinfecting the wound and covering it up for the time being. Sister Superior was too delirious to scream out as Hospitaller sealed the wound using a las-cauterizer. The bleeding had stopped but the source of the injury was now stuck onto Sister Superior that would have to be removed at the convent where better facilities and more helping hands were available.

"And you are one of the adventurers, I presume," Hospitaller asked once she was done. It only took several minutes – she was trained for this since childhood, to cure and heal the faithful of the Emperor as they performed combat duties which she was unsuitable for.

"I am," said the Space Marine curtly. "You created that shield? Aerotech?"

"Yes, sir," Hospitaller replied, pulling out an amulet from her robe. "It is a supporting device used by our Order. It does have quite a few functions, but most are only unlocked as my rank rises."

"What else can it do?" asked the Space Marine. "Aside from creating force fields."

"The device can also release a burst of light to blind the foe at short range, allowing the wielder to escape," Hospitaller explained. "I couldn't use it earlier because…"

"You were carrying your comrade," the Space Marine finished. With a deep sigh, he introduced, "I am the Huntsman, 4th Company, Red Scar Chapter, son of Jaghantai Khan. I am known as Gretchin Slayer."

"Gretchin Slayer….," Hospitaller murmured. What a strange name for a Space Marine.

"And I require your aid," Gretchin Slayer continued. "A bit."

The girl tilted her head slightly. "A bit?"

Within ten minutes they were back at the large gathering chamber where Hospitaller's team had been ambushed. Gretchin Slayer was determined to eradicate the Xenos infestation from this wreckage once and for all – apparently, it was a quest posted by the Mechanicus at the Adventure Guild so that they could come in and plunder afterward. Helping out the man who saved her and her comrade was the least Hospitaller could do, regardless of his intentions.

"Activate it," said Gretchin Slayer.

"Right." Hospitaller complied as she pressed the activation rune and the amulet she carried glowed brilliantly like a tiny sun. Within the dark chamber, every Gretchin was drawn to it like fireflies. Many were blinded by the sudden burst after living so long in utter darkness, but they recovered and adjusted quickly. Within seconds, a throng of the creatures swarmed around the beacon eager to kill and loot and feast on the unfortunates who dared enter their domain. Their foe had given away their position in a battleground where they had the advantage, and they would make the trespassers pay dearly for that. The Gretchins did not charge headlong when it was still so bright and decided to wait for the light to die out – their prey was surrounded and wasn't going anywhere. As the light died out, there was no one there, only the now powerless amulet. It was a ruse all along, and they had fallen for it.

As the bulk of the Gretchin force gathered around the bait looking confused, Gretchin Slayer was on the move. He had determined that the Gretchins were too numerous and organized to be just a wandering mob; instead, an Ork leader must be within the vicinity. A Mekaniak was likely, given the heavy weapon they employed and the fact that inside of a superheavy wreckage was like a dream come true for that specific type of Oddboy. A direct assault against the Gretchins would be unwise, even for an Astartes, so a bit of distraction followed by decapitation of leadership was the plan.

Her role spent, Hospitaller hid behind some cover and watch as the Space Marine's scheme unfolded from a safe distance. Though a member of the militant group under the Adeptus Sororitas, Hospitaller was combat-ineffective and would probably get in the way more than lending any help. As the Gretchins were drawn to the bait, she had taken upon herself to look for her deceased comrades; though it pained her to do so, the advanced weapons they carried didn't come cheap and recovering them was necessary. She found what was left of Flamer-wielding Sister, nothing but char, nothing to salvage, nothing to burry nor be taken as a memento for her passing. A severed hand of Repentia was found still clutching to the Eviscerator still wet with alien blood, but not the rest of the body. Though Repentia had chosen martyrdom to make up for her past sin, her loss would be missed by Hospitaller.

Hospitaller was taught by the convent to love and be merciful to others just as the Emperor loves and forgives. However, with what had happened, she found herself praying Gretchin Slayer would remove all of this filth from the galaxy.

The attack began as a red flare was fired, once again lighting up the chamber. Scores of Gretchin heads looked up above with dumbfounded eyes even as death cast its hand upon them. As predicted, a Mekaniak, Ork Boy with a strange affinity towards technology, was in charge of the mob. Unwilling for close combat like most of his kind, he stood at an elevated position next to the artillery piece mounted on a tractor which was used to defeat Sister Superior. He was the first to die as Gretchin Slayer came in from behind and decapitated him cleanly with a chainsaw. The Gretchins manning the gun soon suffered the same fate.

With the threat of long-range heavy support dealt with, Gretchin Slayer showed no more hesitation in engaging the aliens head-on. Dozens of the tiny creatures didn't see it coming as Gretchin Slayer fell upon them like a tornado. Caught off-guarded and without their leader bellowing orders, the Gretchins were nevertheless convinced that fifty against one was an impossible odd even for a Space Marine. They were to be disappointed.

Hospitaller watched the battle with a sense of amazement. Though this was the first time she had seen an actual Space Marine, she had heard stories of their deeds – this display was not what she expected. Gretchin Slayer put his chainsword to his back and drew a combat knife instead. The combat knife itself was not a weapon in as much as being merely an extension of Gretchin Slayer, allowing him to reach further and striking without having to suffer the cumbersomeness of his heavy armor. Gretchin Slayers hacked down dozens of the foe with his blade, but he punched and kicked, squashed and trampled, backhanded and headbutt many more. Such was the fragility of the enemy and the toughness of the Space Marine that even slight impacts could be fatal. But Gretchin Slayer was no a brute; he wasted little strength and applied just enough force so that the enemy would be dead instantly without overkilling them whenever possible.

The battle became a massacre. The Gretchins' crude weapons were unable to cause even a dent on the Space Marine's armor. Shots bounced off even when fired at point-blank while melee weapons could never reach Gretchin Slayer without a response in the form of a ceramite-clad fist in their face or stomach. At this point, the Xenos began to panic and flee in droves. Gretchin Slayer made sure as few escaped as possible, taking out a stubber – yet another unconventional weapon – to snipe out the fleeing creatures. After a while, the chamber fell silent as the fight concluded.

Fifty-seven confirmed kills. Five confirmed escape. Gretchin Slayer observed vigilantly for any creature he might have missed before turning to Hospitaller.

"I will help you carry your ally out of here," he said. "I know the way out, but before that, there is something I have to do."

"Can I help?" asked Hospitaller.

Gretchin Slayer didn't reply and kept walking. Hospitaller walked closely behind. The Space Marine knew the way out – she had no choice but to follow him. The two of them approached what looked to be the nest, or whatever term to describe dwelling, of the greenskins. There were many mangled, half-eaten bodies there, most of which Orks but some unmistakably human. The aliens apparently had no preference between meat cooked and raw, fresh and rotten, human and their own kind. Hospitaller couldn't tell which part belonged to her fallen sister, nor did she want to know. If the machinery smell was bad, the stench of decay here was unbearable and Hospitaller covered her nose with her sleeve.

Not all of the carcasses were used for eating, however. The aliens seemed to be growing some sort of giant fungus on some of them. Hospitaller recognized them as fungus due to its texture and lack of need for sunlight – otherwise, this stuff grew like trees with many sprouting branches. What kind of evolutionary miracle, or mishap, must have happened that a fungus "tree" ten feet tall could grow from a single dead Ork. At first, Hospitaller thought it to be the aliens' equivalent to agriculture, to grow more sustainable food source – after all, even Xenos must eat and the Gretchins looked to be at the bottom of the food chain when it came to Orks.

"This is how the greenskins reproduce," said Gretchin Slayer.

"What?" Hospitaller asked, confused.

To prove his point, Gretchin Slayer snatched a branch from one of the giant fungi. Under the dimmed light of her lantern, Hospitaller saw it moving. Looking closer, she was horrified to see what appeared to be tiny arms and a small, sharp head. The thing looked like a Gretchin alright, but even smaller and its legs still attached to the large fungus until Gretchin Slayer had ripped it out.

"Is that…Gretchin infant?"

"Whatever you call it," Gretchin Slayer replied. "Devilish creatures, they are. They view themselves as below the Orks but no one else. They have strengths in numbers and accuracy and more rapid reproduction compared to the Orks, yet rarely do they ever utilize them correctly. Still, it is a grave mistake to underestimate them."

Gretchin Slayer crushed the miserable thing in his hand. "This Gargant has only been here for two months, and it takes decades for Ork spores to reach this part of the life cycle. These fungi were brought here on purpose, specifically for Gretchin breeding. The Ork Mekaniac must have been building an army of his own."

"What should we do?" asked Hospitaller, already knowing how he would answer.

"All of this must be burned to the ground," said Gretchin Slayer.

"Now?" asked Hospitaller. She recalled something about the Mechanicus posting the quest.

"The Mechnicus would send an expedition two days later," Gretchin Slayer explained. "Until then, more Gretchins would have been bred from these fungi, or they would be moved somewhere else when the Machanicus arrived. If it is not done right now, there is a chance that there would be more Gretchins to fight in the future and I will not take that chance."

With that, he set fire to the fungi growth using only a blowtorch attached to a spray can that had been filled with compressed promethium. Again, very crude, very economical, very effective. Far weaker than flamers used by the convent soldiers, the weapon did its job in torching the alien vegetation.

At this point, Hospitaller felt uneasy. Killing the Grethins to avenge the fallen and protect those that still lived was one thing, destroying unborn belonging to the enemy was another. "You said an Ork was breeding Gretchins specifically for his purpose," she spoke. "Could we do the same? Is it possible that… they could be convinced to serve the Emperor as well?"

Gretchin Slayer paused for a moment to ponder. "I have heard thoughts about that. Using aliens against aliens. Treating them as if they were more human than they actually were."

"And what is your thought on it?"

"Bullshit." Hospitaller was taken aback by his frankness. "A good Orkoid is a dead Orkoid. That applies also to Gretchins, Snotlings, Squig and fungi that have yet to grow into anything resembling an animal. That is my creed."

The two of them watched the Xenos pyre for a few more seconds before Hospitaller decided it was time to leave. The Astartes guided her way out of the Gargant and even agreed to provide assistance along the way until they made it to the convent where the Mistress and other sisters were worried sick about them. Carrying both Sister Superior and the recovered wargear was too much for a girl who was barely an adult to do alone. It would be difficult to explain what had transpired that caused the death of two members of the team; even more difficult was performing surgery on Sister Superior. Even if she survived the ordeal, her career both as an Adeptus Sororitas sub-officer as well as a warrior was over. All in all, the whole venture was a catastrophy, even if the Gretchin nest had indeed been eradicated.

Yet, as Hospitaller walked alongside Gretchin Slayer, she could not help but be fascinated about him. She had always wanted to meet and interact with a Space Marine; this was not what she was looking for, but it was cool either way.

Today was only the beginning. They would be meeting each other again, very soon.

Addendum: Gretchin Slayer.

Stats: M_6, WS_3+, BS_3+, S_4, T_4, W_2, A_2, Ld_8, Sv_3.

Wargear: Chainsword, frag grenade, krak grenade, melta bomb, combat shotgun (NOT Astartes shotgun).

Universal Special Rules: And They Shall Know No Fear, Combat Shield.

Unique Special Rules:

Slayer of Gretchins: Channeling years of training and experience, Gretchin Slayer does exactly what his name implies. Re-roll all failed To Hit and To Wound against Gretchins.

Onward unto death: Gretchin Slayer's inner vitality has surprised friends and foe alike, giving him a chance to ignore wounds from single-wound instances that would kill him on 4+.

Faction Keywords: Imperium, Adeptus Astartes, White Scars.

Keywords: Character, Infantry, Gretchin Slayer.

*Note: Gretchin Slayer is based on Space Marine Veteran but has one more Wound and Attack. He also lacks the usual Astartes weapons including boltgun and bolt pistol. A lone Adventurer would not be able to acquire much ammo for these, not that he needs them for slaying Gretchins anyway.

Author's Note: A huge disclaimer to start off. This story is not about people traveling into another universe, it is about what would happen if there is a Space Marines in Warhammer 40k and all he cares about is killing Gretchin. There is also the fact that characters in the anime and manga are named after their unit class, which the Warhammer 40k universe can provide in ample supply as it is also a tabletop game at its core.

I originally wanted to write an Age of Sigmar story with Goblin Slayer a Stormcast Eternal who got killed by Goblins in his past life and vows revenge on them. However, it seems people aren't into the new universe while I am not into the now-dead Warhammer Fantasy as much as Age of Sigmar. So 40k would have to do.

There are several differences in both universes, including the Sister of Battle using mainly Carapace Armor instead of the more expensive Power Armor. Also, since Gretchin Slayer is from the Red Scar Chapter (a nod to his glowing red eye), he will have the White Scar culture as well.

Hope you enjoy. There will be more characters from Goblin Slayer showing up as Warhammer 40k version. Can you guess which Warhammer 40k unit type would they be?