Here's the background for my Alien-themed Tyranid Army.
PLEASE REFRAIN FROM POSTING UNTIL I SAY.
Now, read on, and enjoy

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Part 1
Chapter 1
The Hunted
Moloi's heart was pumping a mile a minute. Not since landfall had he actually developed a sense of fear on this broken landscape. He ran as fast as he could, the mud and gravel making a combination of sloshing and crunching beneath his heavy boots. The rain fell hard, every raindrop obscuring his sight as if to handicap him. He could hear many loud footsteps behind him. Bloodthirsty beasts skittering after him, trying to attain their prey. He kept running, but he grew tired and knew they would soon be upon him. He could hear the faint sound of gunfire, the other Imperial forces of his regiment perhaps? Holding off the last of the planets vicious inhabitants? He gave a sigh of relief at the though, giving him the strenght to keep running for his life. The all-too familiar sound of gnashing teeth behind him grew closer, and to his horror, he slipped on the slick earth beneath him. He gave a gasp, spinning around, his lasgun prepped to fire. The first beast could be seen in the distance, a black figure with sharp claws and serrated teeth. He held his breath and fired. The creature went down, but two more replaced it. Moloi fired frantically into the rain, the creatures bobbing and weaving out of the way of his un-aimed lasgun shots. Moloi closed his eyes as his lasgun clicked out of ammunition.
The beasts were roaring, as if they knew he was defenseless, but something unexpected happened. A woosh of flame poured over his head as opened one of his eyes. The beasts wailed in pain before dying, their charred remains making ash-filled puddles after being doused by the rain. Moloi quickly bounded to his feet. "You alright there Moloi?" inquired Bourne, a fellow guardsmen. He was a powerful man, the heavy flamer tanks on his back were insignificant for the rippling muscles all over his body.
"Yes, I'm fine," he said, limping towards the charred corpse of one of his attackers. It's pitch-black eyes were still wide open, a fearsome scowl adorned its face even in death.
"Fiornian hounds," said Bourne "the natives use them as a kind of hunting dogs. They're pretty nasty in packs, you're a lucky man Moloi." Moloi breathed a sigh of relief, he realized now how much pain he had in his left ankle. He must have twisted it when he fell.
"Somehow I don't feel so lucky Bourne," he chuckled.
"Oh stop your griping, I'll take you back to
HQ, get a medic to fix you up. C'mon then." Bourne helped Moloi along as they head towards
HQ. The sound of Valkyries soaring overhead blew away the insignificant sound of the rain. Moloi looked into the distance, he could see the light outlining the barricade of sandbags. Heavy weapon teams, autocannons at the ready, adorned the line. His fellow guardsmen, the ones he knew on a personal level, waved him hello, many of them patting him on the shoulder as he limped past the barricade. Bourne guided him to the medical tent, laying him down on a bed while he went to talk to a medic. Moloi was tired, he couldn't remember the last time he had slept since touchdown. He saw the medic walking over to him as he passed out from exhaustion.
Chapter 2
A Warning Unheard
"This is madness! You cannot disrupt our preservation of the deep ones!" said the tall, lanky native. It's skin was a dark, motteled brown, covered in random splotches of black.
"Shut up you," said a guardsmen, hitting the native with the butt of his gun. "there's not gunna be any debating or discussion! This is a hostile takeover donkey-cave!" The line of natives continued towards the camps for execution. The amount of Imperial casualties due to native resistance numbered in the thousands. They had refused to submit peacefully, and for that, they would die.
"Any last words xenos scum?" said the comissar, his laspistol primed for the natives head. The native lowered its head slowly, then quickly raised it, sending a hot loogie in the face of the executioner. The comissar was revolted, both he and the guards pouring fire into the native. "Disgusting scum! Send in the next one!" he said as the guards dragged the native's ravaged body outside into the pit where they were burying the dead. The next alien was brought in. A magnificent pattern of blue tattoos adorned the creatures body. It was put to the front of the room, the blood of the dead staining his feet. "You going to be all pissy about this too?" The xeno was silent. "Huh?!" The xeno lifted his head up a neutral expression on his face.
"I am king Kahlun and I emplore you to stop this. You cannot stop our preservation of the deep ones," he said with a solemn look on his face.
"Deep ones, deep ones, deep ones. I think you xenos are just trying to scare us off. There's a plethora of valuable resources beneath the crust of this planet and we're going to dig until we make it hollow!"
"No you can't! You will awaken them!"
"I don't care, the fist of the Emperor will crush any deep ones that stand in our path."
"You cannot stand against them. They will devour you all. There will not be an ounce of life on this planet when they are finished."
"I grow tired of your warmongering," said the comissar, raising his pistol.
"You will be engulfed by your own greed. The deep ones will overwhelm you all. Your Emperor will be a bloodstain on the floor!"
"Such blasphemy is intollerable. Guards, take him. We are going to prove a point." The king was dragged outside, in front of the natives. Gasps and screams were heard as the king was put to his knees.
"This will be the fate off all that threaten the Holy Emperor's will!" said the comissar, nodding to Bourne. The comissar backed up, a gout of flame engulfing the blasphemer. The alien screamed in pain, running around frantically trying to put the flame out, but to no avail. He curled up in pain as his charred corpse sizzled and cracked. The aliens all turned away, some of them openly weeping. "Get back in line you scum!" yelled the comissar.
"Lord comissar!"
"What is it," he said turning to the guardsman.
"Some of the scanning parties are reporting the mountain in north sector 5 is rich in ceramite ore."
"When can we begin excavation?"
"In less than three weeks, sir."
"Emperor be praised! Notify the excavation teams to begin preperation procedures for drilling. I want them ready asap."
"Yes sir! Right away sir!" said the guardsman, heading towards communications.
"Deep ones," the comissar scoffed, walking back into the execution room, not realizing the fatal error he had just made.
Chapter 3
Nothing on Record
Five weeks later...
"Deep ones? Nothing I've ever heard of," said Inquisitor Crowe to the Commissar. "Let me search the Imperial records," he said motioning over a servitor. "There doesn't seem to be any recordings of any hostile organisms in that sector that have been designated as deep ones. Perhaps they are a deity of the natives?"
"The natives are saying that there are their keepers. They're afraid we are going to wake them up through our drilling operations." The Inquisitor eyed him suspiciously, looking more intently through the Imperial records. Crowe had a high standard in the Ordos Xenos, a veteran of many campaigns against the alien scum, including his most famous in an action against the Genestealer cult on Argus IV.
"I don't know. There's nothing on record, but we should be weary during our excavations," he said, still intently looking through the records.
"Lord Inquisitor, with all due respect, should we really be worried about the vengeful gods of some misbegotten xenos?"
"Just because it isn't on record does not mean it does not exist. Do not ignore the possibility that there may be something we're not seeing," scolded the Inquisitor.
"Yes Lord Inquisitor," the commissar added.
"It may be wise to have your forces aid the miners in their excavations in the event that there is some form of hostile organism. When we begin mining of course," Crowe said, obviously ordering without saying so.
"When we begin?" the commissar said, puzzled.
"Yes," the Inquisitor said sternly, raising an eyebrow.
"Excavation procedures began a week ago, sir," stated the commissar. "So far none of the mining teams have reported any hostile organisms. It's all rock, no indigenous life under there."
"Still, I believe it would be wise to send some guardsmen to secure the area, we can never be too sure."
"But sir, I-"
"Do you question my will? I am the word of the Emperor? Do you question his will?!" the Inquisitor berrated. The commissar backed off.
"No sir, I will send a guard regiment to north sector 5 to help against any deep ones."
"As I thought. Emperor be with you," the Inquisitor said, going back to his studies. The commissar went out of the tent, barking orders in order to take out his frustration. He turned to the servitor once more.
"Search the Imperial records for any traces of unknown minerals recorded to be found on this planet." The servitor searched the records intently, bringing up a glowing display. A mechanical voice talking through the servitor resounded.
"Records show traces of an unknown substance found in native species' religious buildings."
"Origin?" the Inquisitor inquired.
"Unknown."
"Any connections to other known minerals found in this galaxy?"
"No. Substance has been categorized as extragalactic."
"What category does this substance fall under?"
"Organic," the screen shut down. Inquisitor Crowe began turned away puzzled. He had a thought, but ignored it as fabrications. He returned to his work, the thought echoing in the back of his mind.
Chapter 4
Wild Goose Chase
"Man this is
bs!" Bourne stated. They were on a Valkyrie, one of three sent to north sector five to intercept any and all hostile organisms that were terrorizing the miners.
"Shut up Bourne, no-one wants to hear your fat ass complain," said Vark, a medic.
"Well I'd just like to know why command's sending us to hunt some ghosts in a mountain."
"Apparently there might be some hostiles in the underground. Even if it's nothing, it's better than sitting in the sun all day waiting for something to happen," Vark reasoned.
"Yeah whatever. I still say this is
bs," he said, sitting back down. He pulled a cigarette from one of his pouches, lighting it.
"Man put that gak out," said Moloi.
"Shut up; if I'm gunna be sent on some wild goose chase on my R&R, I'm gunna smoke! I already saved your ass, so quit complaining." Moloi glared at him, fiddling with his Lasgun. Their entire squad was here. Moloi, the new guy. Bourne, the hothead flamer-user. Vark, the medic. Dietrick, the heavy weapons expert. Johnson, the tech. And last but not least, Gorman, the seargent. They'd been through alot on this planet; covert ops back when they were still taking the natives by storm.
"We're appoching the drop point," the pilot said through the intercom.
"Alright guys, get ready," said Gorman. The valkyrie hit land and the rear hatch opened. "Green light! Go!" The squad charged out of the dropship, the other squads two and three coming out of theirs nearby. They looked around, no-one there.
"They must be inside, drilling," said Dietrick pointing his plasmagun to the iron door leading into the mine.
"Alright, first squad, move in," commanded Gorman. The other squad seargents gave their orders, seconds squad following first, third waiting outside.
"Johnson, run a bypass," said Gorman. Johnson approached the door, connecting his hacking device into the terminal, and after punching in a number of codes, the massive mechanical door, wide enough for a baneblade and tall enough for an Imperial Warhound titan, slid open with the loud grinding of mechanical gears. Utter darkness filled the tunnel. There were no miners. No machines grinding away at the precious Ceramite. Nothing, just complete darkness.
"I've got a bad feeling about this," said Vark.
Chapter 5
Movement
Squad one moved through the dark tunnels of the mine, their only source of light being the small shoulder lamps on their armor pads. It was quiet down here; the only noise the sound of their boots, the wind blowing through the tunnels, and the ocasional drop of water that echoed in the small puddles. "Everyone stay on your toes," said Gorman. They continued to walk through the shadows. "How man feet down are we Johnson?"
"About two hundred feet, sir, I don't know-" Suddenly, a loud scream was heard to their left, cutting off Johnson. The shouts were accompanied by the sound of crashing and snapping bones, before ending with a loud thump.
"Who was that?!" Gorman asked, urgently. "Soudoff!"
"It's Bourne, sir!" exclaimed Dietrick. He shined his light to a small hole that had opened up in the ground.
"Oh bloody hell! My leg!" Bourne yelled up through the hole in the ground.
"I told you to lay off the snacks, Bourne," Vark chided, he could faintly see Bourne giving him the middle finger down through the shaft.
"Hang on Bourne," said Gorman. "We'll get you up. Moloi! Bring up a rope."
"Are you okay." Said the seargent of squad two.
"Please; kill me." Said the bloated miner, leaning up against one of the rock walls of the mine.
"What the hell happened down here?"
"The natives- the natives- were- were-" the miner suddenly began convulsing. He proceded to throw up a fountain of blood before going limp. The seargent went over to him, pressing his fingers against his neck.
"He's dead. Call up squad three and tell them to radio in command, they need to-," just as he was about to finish his sentence, an array of jaws bursted from the dead miner, gripping the seargents arm in a silver bear trap of fangs. The squad proceded to rain lasgun fire on the creature. To their horror, the creature sprayed blood all over the seargent, which proceded to melt him away in a smoke with the stench of burning flesh. The seargent writhed in pain before dieing from his burns.
"What the hell was that?!" one of the squad members yelled, scared out of his mind.
"We need to get the frak out of here." Suddenly, they heard the sound of clicking coming from the lower tunnels.
"I've got movement!," said another guardsmen. He turned to the guardsman nearest to the tunnel, shining his light at him, and giving a face of horror.
"What?" the guardsman at the top of the tunnel asked. Behind him, a figure stood behind him. Only its outline could be seen, and the light being shown on it was distorted, as if it was being shown through a perfectly clear crystal. The guardsman with the light tried to warn him, but it was two late, the invisible creature was upon him, lifting him up with it's now un-cloaked tail, impaling him through the chest. The guardsmen all screamed as the massive creature jumped from wall to wall. The darkness aided it in making it almost impossible to pinpoint, and every second the amount of screams decreased by one. The last guardsman, sitting down up against a wall, prayed to the Holy Emperor. He heared a low clicking right above him. He looked up to see the eyeless, glossy black head of the monstrous creature, before his head was ripped off by the creature's massive jaws.
Chapter 6
Survivors
"Bourne are you alright down there?" Gorman yelled down as he began to uncurl the long rope.
"Yeah, but god does it stink down here," he said squinting his eyes in hopes of seeing the source of such a dreadful smell. "Can someone throw down a flare?"
"Sure," said Vark, tossing down a flare. Bourne caught it, setting it off. He recoiled from the light, allowing his eyes to adjust to the bright light. His eyes then grew wide at the horror that filled the area all around him. He had found the miners. Glued to the walls by some mucus-like membrane that constantly riled and pulsed. The chests of the miners had been bursted outward, their ribs splayed out. Blood littered the floor, and suddenly Bourne began to notice that even the floor was coated in this living mucus.
"Guys," he said, his voice quivering. "I found the miners."
"Survivors?" aked Gorman.
"No sir, they're dead."
"Dead; how?!"
"No clue sir but it's a nightmare down here," suddenly he heard a slithering noise coming from all directions. "Sir there's something down here! Where's that rope, you gotta get me outa here!"
"It's coming, just gotta untangle this last bit," said Moloi. The slithering began to get louder, and more consistent.
"Hurry the frak up! There's something squirming around in this cave!" he yelled.
"Okay we're throwing the rope down now, grab on!" said Moloi. The rope was tossed down, making a splashing noise as it hit the mucus-covered floor. Bourne began to tie it around himself in a harness. The slithering was getting louder and louder. The flare slowly went out.
"Bourne, you got that gak tied up?" asked Gorman. There was no answer, but the rope tensed up slightly, giving them the signal to pull him up. Gorman nodded to the rest of the guys as they began to tug at the rope. Suddenly, without warning, the rope tensed up with such force that it began to pull the rest of the squad towards the hole. "By the Emperor's name!" yelled Gorman as he and the squad wrestled with the rope like an old man that had just caught a huge fish on his line. After much pulling, the line suddenly went limp. They quickly pulled up the line. The tension mounted, when suddenly Bourne's head could be seen rising from the hole in the ground. They breathed a sigh of relief before realizing the horror that was upon them. Bourne's body had been severed at mid-torso.
"Throne, what the frak did this?!" exclaimed Dietrick.
"What's in this place?!" added Moloi.
"Okay, we need to call in back up. Johnson, get squad two on the horn." ordered Gorman.
"Squad two come in, over," but there was no reply. "Squad two do you read? Over," still no reply. "No reply, sir." Suddenly they heard loud screeching on top of skittering coming from the tunnel. "Sir..."
"What is it Johnson?!" replied Gorman, trying to see what was making the noise down the passageway.
"I'm picking up movement."
"What's the position."
"Down the tunnel. Multiple signals. They're closing," he said gaping at the scanner. "Oh man this is a big fraking signal."
"Dietrick, fire of a plasma shot down the tunnel." Dietrick raised his gun, shooting a bright blue plasma round right down the passage. It hit nothing, but the blue light revealed something horrifying. All down the cylindrical walls of the tunnel, there were hundreds of black creatures crawling along the walls. All the men turned to one another. "Emperor protect us!" He said, giving the hand motion to fall back. The squad laid down supressive fire as the creatures swarmed towards them. Suddenly, the floor opened up beneath Dietrick, sycthe-like claws of one of the creatures chopping his legs out from under him. The squad kept moving backwards as the swarm of creatures climbed over him, ripping him to pieces.
Vark tried to set up a demo charge in front of the swarm, but he was picked up by his head and pulled into the ceiling by one of the creatures. He squirmed trying to get out of the grip of the monsters, but his face was engulfed in an aray of tentacles, and he could feel them squirming into the orifices of his face as they ripped his skull open and sucked out his brain. They kept on running as fast as they could, they had dropped their guns as it was hindering their speed. Suddenly a ray of hope, the light at the end of the tunnel, leading to the outside. "Johnson!" yelled Gorman. "Tell squad three two ready defensive positions. We can hold-the line once-" but Gorman was cut off as a massive claw errupted from the ground, clenching him in its might. With little trouble, the crab-like appendage squeezed him tight, ripping him in half. Blood spray covered the glossy, black carapace of the massive creature, who had now stepped out of the hole it came out of. Johnson and Moloi used its size to their advantage as they weaved through the creatures legs, it's cumbersome size making it hard to catch them.
"Squad three, ready the Valk's! It's a damned ambush!" yelled Johnson over the comm link.
"We read you loud and clear." said a guardsman of Squad three. All the guardsmen began to get into their Valkyries. Moloi and Johnson were almost at the entrance when suddenly, an invisible creature made itself distinguishable right in front of the cave. The creature leaped towards Johnson, its mantis-like limbs striking him and tearing a huge gash across his chest. Moloi managed to weave past it, but turned back to see Johnson get stepped on by the massive, clawed behemoth. His body was turned into a bloody puddle that made an audible gushing sound as the creature stepped with the remnants of his comrade stuck to his foot.
Moloi kept running until he was out of the cave. He sprinted towards the Valkyrie of his now non-existant squad, as the Valkyrie of the third now prepped for takeoff. Suddenly, massive globs of slime engulfed the third's Valkyrie, as it slowly melted under the acidic slime. Moloi's Valkyrie was hovering above ground, the side hatch open to allow him to jump in. With the last ounce of energy he had left, he jumped into the door, as the Valkyrie soared off towards
HQ. Moloi looked back down at the swarm of writhing black creatures, to get a good look at what killed his brothers. It was then that he realized the true threat that they faced.
Tyranids