A Requiem for Friendship

by Mkchief34

Rating: teen
Tags: Gore, My Little Pony: Friendship is Magic, Princess Cadance, Dark, Other, Adventure, Science Fiction, Princess Celestia, Crossover, Alternate Universe, Human, Twilight Sparkle
Length: 3664

Twilight, after being cast out of her brother's wedding, messes up a teleportation spell that sends her to the Forerunner world of Requiem, just as the Forward Unto Dawn crashes. And thus begins a new adventure for Twilight Sparkle...

Twilight Sparkle is sure Princess Cadance is an impostor. And yet, no one believes her. Cast out from the wedding due to her accusations, she attempts to teleport to Ponyville for a breather, only for a magical misfire to cause a torrential Slipspace Rupture that sends her to the Forerunner world of Requiem...

Just as the Master Chief and the Forward Unto Dawn crash onto the world's surface. And thus begins a cataclysmic adventure for the young unicorn...from battling the Covenant and the newly-revived Prometheans to her own demons, will Twilight Sparkle stand strong and make it home in time to save everything she cares about?

And in Equestria, the real Cadance manages to expose the Changeling Queen, but will the ponies prevail without Twilight? And will Equestria survive?

Only time will tell. And the Requiem is already being composed...
====
Halo 4 crossover, set in Season 2. Will have swearing, gore, and Halo-esque imagery.

Published 2017-11-15 17:50:06 UTC
Last updated 2018-03-12 14:43:00 UTC

Prologue-The world of Metal

Canterlot

Private Chambers

Twilight Sparkle, tears streaming down her eyes and cheeks, limped into her room and collapsed on her bed, crying like a newborn infant.

"Why?" she moaned into her blankets. "Why...won't they believe me?"

She sobbed for a few moments, remembering that even her mentor abandoned her, harshly rebuking her and banishing her from the Wedding.

"No…" she whimpered again, brushing her tears away. "That's it. If they don't want me here...so be it."

Twilight charged up a teleportation spell, attempting to return to Ponyville. As the magic formed around her horn, and the mental image of her destination appeared in her mind, she flinched when she saw that the normally lavender glow was a bright electric blue, and sparks of lightning were crackling off her horn. Twilight, realizing her spell had backfired, or was about to do so, attempted to cancel it.

However, it was too little, too late.

The spell backfired, causing a crackling blue orb to form around her, Twilight's screams echoing louder as the orb enveloped her, then it collapsed, blowing everything around her into fragments, and then…

Twilight Sparkle was gone. Not too much later, Princess Luna opened the door, and when she saw the carnage, there was a gasp, and cry, and the clatter of hooves.

====
Forerunner world of Requiem

Unknown Space

Twilight groaned and rubbed her eyes open, gasping upon seeing her environment. She wasn't at Ponyville. In fact, she didn't know where she was at all. The terrain was foreign, and she could see large metal chunks of debris around her. It looked like something large and metallic had crashed recently. Similar metal objects, colored purple, were also strewn about.

"Where am I?" she murmured. "What happened here?"

Twilight looked at the area again, and sighed.

"No need to panic." she reminded herself. "So, instead of heading to Ponyville, I'm stuck in...Celestia-knows-where, with a bunch of metal objects and detritus. I'm not on Equis anymore, that's for sure...and I'm scared out of my wits."

She groaned, and deciding it was better to get moving then to stay, she started to walk.

====

It wasn't much later when she saw her first sign of life. A hulking, bipedal beast plated in armor appeared in her vision, causing her to jump into hiding. She looked at the alien carefully. It was bipedal, with hooked legs and a flat, mandibled head. It stumbled slightly as it reached for its shoulder, and Twilight realized the alien was hurt. Taking a gamble, she called out.

"Hello?"

The alien spun around, and upon seeing Twilight, gave a low rumble.

"Are you okay?" she asked again. The Elite growled and drew an Energy Sword and ignited it, lunging for Twilight. She fired a blast of magic and stunned it before running like high heaven away from it. The Elite, though wounded, kept pace, and eventually cornered her when Twilight dove under a pipe-shaped piece of debris with no exit. The Elite started to slice up the pipe, segment by segment, in order to force the creature out. Twilight, knowing she was cornered, screamed as loud as she could muster.

"HELP ME!" she yelped, causing the Elite to flinch, then to slice her cover apart far more quickly, eventually succeeding in driving Twilight out. She cowered in fear and panic, and as the Elite raised his sword to impale her…

A single gunshot rang out through the clearing.

===

Twilight saw the alien collapse to the floor, a large hole in its head leaking blue blood and ichor. She hastily scanned the area, looking for whatever killed it. Then, she heard footsteps. She looked in front of her to see another alien come forward slowly. This one, though still bipedal, was plated in green armor with a golden visor, and it carried a small, white, L-shaped object. A larger gray object was on its back. It walked forward slowly, holstering the small object. She could read three numerals on its chest plate.

117.

Twilight tensed up, waiting for death to come as the alien neared her.

Only, it didn't. The alien knelt in front of her, and spoke in fluent Equish.

"You alright?" it said, in a deep voice that reminded Twilight of a hardened warrior. Twilight nodded hastily, still shaking in fright

"Good. Stay close to me." the alien replied, pulling her up. "We need to get moving."

"Who...who are you?" Twilight managed to stammer. The alien turned and the next words it said would change her forever.

"Call me Master Chief."

====

Back in Canterlot, in the Crystal Caverns, the real Princess Cadance walked through another stratum of crystals, having long lost her way earlier. She sighed, and leaned on a cavern face populated with gems. Suddenly, she heard a faint humming, and the cavern wall disintegrated. Cadance gasped upon seeing a metal hallway lined with green glyph markings and beams of glowing energy. Cadance wanted to run, but her curiosity got the better of her, and she started to walk down the path.

After a few moments, she arrived in a large cavern with a domed ceiling, and countless beams of energy cascaded across the ceiling. At the end of the path in front of her was an altar of some kind. She walked over to it, and touched it. A beam of green energy covered her, and after her vision cleared, Cadance saw her ragged coat and mane had been restored to its normal sleek and curled state. And furthermore, her magical reserves had been replenished. She prepared to teleport to the wedding hall, only to cancel the spell at an odd sound.

Humming.

She looked to see a small metal orb with a ringed body float near her, humming a tune. Cadance stayed silent out of fear, then she noticed that orb didn't seem to know she was there.

"Hmm...hmm...hmmhmmhmm..." it chirped, Cadance seeing its eye, a bright green lens pass it as it neared the altar before it scanned it.

"Well, that's odd." it spoke in a elderly, kind voice. "No unauthorized access detected...must be my imagination. Well, seeing as my 13.15 thousand cross-checks didn't find anything..."

It then looked at Cadance, and the two of them screamed.

"AHHH!" Cadance cried.

"Gah!" the orb yelped. "Well, Pardon me! I didn't think I'd have visitors so soon! That's why the access beacon went out! Silly me, I thought it was my imagination!"

"What are you?" Cadance asked, putting a hoof to her mouth.

"I am 153 Pious Deacon, Forerunner Monitor of this Installation." Deacon said. "Who are you?"

"I'm Princess Cadance." she said. "Where are we?"

"You are currently in the Forerunner Control Room of Shield World Ascendance." Deacon said. "And surprisingly, I didn't know life developed here independent of the Librarian's actions! Fascinating! Tell me, what's going on up top?"

"Up top?" Cadance asked.

"Of course! Up top, above ground?" Deacon said again.

"Well..." Cadance said, giving a hurried explanation of the wedding. Deacon flinched, and then, he laughed.

"That will not do!" he said. "That is a clear violation of the Guidelines established by the Forerunners for this Shield World! If you'll allow me, I can address it!"

"How?" the Princess asked. "We'll need an army..."

"I have an army!" Deacon said with glee. "A countless army of Promethean Warrior-Servants, at my beck-and-call! If you want, I can activate them and this violation will be fixed in no time!"

Cadance hesitated, then she nodded. Deacon pulsed a green aura, and the forms of countless Promethean Watchers, Knights, and Crawlers appeared, ready for combat.

"All of you know what to do!" Deacon said. "Take care of these brutish Changelings!"

The Prometheans cried out and vanished into a Slipspace portal. Cadance then saw a second portal open behind them.

"Let's go!" Deacon said.

"Where are we going?" Cadance asked, confused.

"Where do you think?" Deacon said with glee. "Up top! You're getting married, remember?"

Cadance and Deacon jumped into the portal, and in a flash, reappeared in the wedding hall, startling everyone present, especially the Cadance currently at the altar.

"Impossible..." Celestia murmured.

"What?" Rainbow cried. "Why's there two of them!"

Many others in the crowd murmured in shock.

"Because that one's a Changeling!" Cadance cried. "You're through!"

Chrysalis laughed and revealed herself to the crowd.

"Right you are, Princess." she cackled. "I thought you wouldn't make it in time! Pray tell, how'd you do it?"

"I had help." Cadance said, as Deacon came into view.

"Hello. I am 153 Pious Deacon, Forerunner monitor of this Installation! And you, Changeling are in violation of the Guidelines! I would advise immediate surrender!"

"Hah!" Chrysalis laughed. "I have an army!"

"We have one, too!" Deacon laughed joyfully as countless Prometheans, glowing blue, appeared and raised their weapons. Chrysalis stopped laughing and looked at the small orb and the Pony Princess.

"Now, would you like to do the honors?" Deacon asked Cadance, who nodded.

"Get her." Cadance growled as the Prometheans opened fire.

Chapter 1-Spartan

Twilight scrambled to her feet as Master Chief started to walk away.

"Wait!" she cried. Chief looked over his shoulder at her, almost as if expecting something.

"Where are we going?" she asked. Chief merely shrugged.

"Away from here." he replied. "Let's get moving."

Twilight nodded hastily, and set out after the Spartan. Master Chief looked once more at the dead Elite on the ground to confirm the kill before heading to a ridge, Twilight following.

====

After around twenty minutes of walking, the pony and the Spartan exited the crash site, revealing a cliff with a gorgeous view of a valley, peppered with large metal spires shaped like obelisks. Twilight made sure to implant the sight in her memory before Chief snapped her out of her trance.

"Let's move." he said. "Cortana, can you find us a transport?"

Twilight raised an eyebrow, looking at the Spartan questioningly.

"Who are you…" she started to speak.

"There's a vehicle bay near here." said a female voice, seemingly coming from nowhere. "Seems your luck is holding out, Chief."

"Who's there?" Twilight asked. Chief reached for his helmet and pulled something out, holding it to her. Twilight then saw a small humanoid figure, blue with short hair, appear in front of her.

"I'm here." the figure said. "I'm Cortana. I'm a UNSC AI, registered to Chief here."

"Nice to meet you." Twilight said. "What's an AI? And the UNSC?"

"That's a...long story." Cortana replied. "Let's wait until we have some solid transport before we start talking."

Twilight nodded. Chief placed the chip back in his helmet and motioned. After a further five-minute trek, they found a large hangar, or what remained of it. Twilight then saw three large metal carriages, with some kind of mounted object on the back, waiting for them.

"Warthogs!" Cortana said, almost relieved. "Already fueled. Let's load what we can, and get moving."

"Right." Chief said. Twilight hopped into the designated Warthog, and watched Chief load two bags marked "UNSC" onto the back. He took the wheel, and with a small "eep!" from Twilight, it gunned forward into the valley below.

====

"So, Cortana?" Twilight asked once she had settled into the passenger seat. "Where do we begin?"

"I honestly do not know." Cortana replied. "In the whole history of humanity, we've only had one first contact, and those aliens ended up bringing us to the brink of extinction."

"Okay, first, Master Chief is human?" Twilight asked. "They're myth back on Equis."

"I presume that's your homeworld?" Cortana asked, and Twilight nodded. "Yes, Chief is human, and as for the other aliens we met, they called themselves the Covenant. A conglomerate of different species, all following a single religious creed. They believed Humanity's mere existence was an affront to their gods, and they started the Human-Covenant War which lasted twenty-seven years, and killed over twenty billion humans, and countless worlds were burned and turned to glass."

Twilight was absolutely floored. She fell back in her seat, starting to cry.

"How did you win?" she finally asked.

Cortana gave an explanation of the Halo Rings, the Great Schism of the Covenant, the battles on the Ark, and their being stranded aboard the Forward Unto Dawn for four years. Twilight nodded, still shocked about the war's destruction.

"Right now, we're trying to find some way to contact the UNSC so we can go home." Cortana said. "But...I'm not sure I'll make it."

"Are you okay?" Twilight asked. Cortana sighed.

"AIs such as myself are built to last seven years. I've been in service for eight." Cortana said sadly. "Any longer, I start to develop a condition known as rampancy. My functions start to degrade over time, and eventually I die."

"Is there any way I can help?" Twilight asked.

"There's no known cure for my Rampancy." Cortana said. "Thanks for offering. Chief, we've got contacts. Covenant staging area, by the looks of it."

"I thought you had a truce with them!" Twilight said.

"These are likely remnants of the old Covenant, those who stayed loyal to their religion." Cortana said. "And just so you know, they won't be happy to see us. Be ready for a fight."

"Right." Twilight nodded. Suddenly, the Master Chief cut the engine and exited the Warthog, readying his Assault Rifle.

"What is it?" she asked.

"Covenant." Chief replied. "Get to cover."

Twilight exited the Warthog and dove behind a rock. She peeked out to see a few additional Covenant she had not seen before. There were small, simian-like ones wearing large packs, and lean, rangy lizard-like ones with shields. All were being ordered around by the Elites that were stationed around the area. Chief made his way to Twilight, and tapped her on the head.

"Can you fight?" he asked quietly. Twilight nodded.

"Good. Stay with me." he said again. Chief slowly snuck up behind an Elite, and plunged his knife under his neck. The Grunts in the Elite's patrol spun and looked straight at the Master Chief, weapons ready.

"Boo!" Chief barked, raising his Assault Rifle.

"Demon! RUN!" the Grunts cried, alerting the rest of the Covenant soldiers. Twilight ignited her horn as Master Chief opened fire.

====
Equestria, Canterlot
Wedding Hall

Chrysalis barely had time to dodge the Hardlight bolts that peppered the area where she once stood. The Knights advanced, growling and roaring while firing at the Queen. Chrysalis threw up a barrier and initiated her hive-mind link with her army.

"I am exposed! Attack the city immediately!" she thought.

"At once, my Queen!" was the reply from her Generals, and the Changeling horde appeared on the Horizon. The sky soon filled with Hardlight blasts from the Promethean troops. Cadance seized the moment and blasted Chrysalis full force. The Queen was sent flying, but she recovered and fired back.
"You Ponies will not defeat me!" she cried, lunging at a Knight Battlewagon. The Knight merely slashed her across the chest with his Blade. Rolling along the floor while clutching the wound, Chrysalis moaned in agony. The wound was not bleeding due to the Hard Light cauterizing the damage immediately, but it still tore a very large gash in her chest. Five Watchers summoned Hardlight bindings, and restrained the Queen.

"That's how it's done!" Deacon said. "Warrior-Servants, detain her!"

The Lead Knight clicked and barked, and the Prometheans, along with the Queen, vanished into Slipspace. Cadance sighed, and looked at a still-hypnotized Shining Armor. She sighed, and slapped him full in the face, which broke hm out of his trance.

"Ow…" he groaned. "Wait, Cadance? What's going on? Why'd you slap me? Is the wedding over?"

"That'll be quite a story!" Deacon said. "I am 153 Pious Deacon, Forerunner Monitor of this Installation! And you have missed quite a bit!"

Cadance said nothing as she hugged him tightly, then she realized somepony was missing.

"Where's Twilight?" she asked. At that, Luna walked forward.

"She is no longer here." Luna said sadly.

"What do you mean?" Cadance asked. "No longer here? What happened?"

"She attempted to teleport home to Ponyville." Luna sighed. "Due to her emotional distress, the spell backfired. I am led to believe by the scene…"

"...That Twilight Sparkle is no longer on Equis."

====

Twilight fired off a beam of magic at a Jackal before diving behind a Forerunner barrier. After clearing the Covenant at the staging area, they had ventured deeper and discovered what Cortana called a "Cartographer". After fighting more Covenant, they were heading for a Terminus that would allow them to contact a nearby UNSC ship, the Infinity form what Cortana could gather from the splintered comms signals.

"What now?" she cried to Master Chief, who was engaged with fighting a pack of Elites. Chief hurled a Plasma Grenade and dove to meet her.

"We focus fire on my mark." Chief replied. "Mark!"
The Unicorn and Spartan opened up with a volley of bullets and magic, and the Elites were dead in minutes. Chief stood up, followed by Twilight, and they entered the Terminus.

"What do you think we'll find in here?" Twilight asked Cortana.

"I have no idea…" she replied as the doors closed behind them.

Chapter 2-Cartographer

As Master Chief and Twilight Sparkle advanced through the dimly lit hallway, Twilight's eyes jumped from shadow to shadow, frightened that at any moment, more Covenant would attack.

"Here's the Cartographer." Cortana said with relief. "Plug me in."

A second set of doors opened, revealing the Forerunner machine. Chief plugged Cortana's chip in, and she appeared.

"Strange." she murmured. "The Cartographer is fighting me, it's not wanting to triangulate the Infinity's signal."

"Infinity?' Twilight asked.

"A UNSC Ship we're trying to contact." Chief said.

"Phew, I got it." Cortana sighed. "It's right here, somehow it went deeper than we did. I got the portal open, we're set."

Chief removed the chip from the console, and a metallic screeching could be heard. It was a sound that set the unicorn's teeth on edge.

"What was that?" Twilight cried. Then blue lights coalesced around them in a rough half-circle, and strange metal beasts appeared. Twilight immediately reasoned they weren't happy to see them.

"Cortana, let's go!" Chief barked as the portal came to life.

"Don't wait on my account!" Cortana replied as the Prometheans readied their weapons. Twilight and the Spartan dove through, Twilight dodging the blasts of Hard-Light.

====

The two of them tumbled out and into a large area, filled with Forerunner architecture. Walls of blue rock towered above them, and Twilight got a nervous feeling in her stomach.

Chief took a step forward, and one of the metal beings jumped onto him.

"Chief!" Twilight cried, blasting the Knight with a beam of magic. The Knight revealed its face, before teleporting away.

"You alright?" she asked, pulling the Spartan up. "What was that?"

"I'm not sure." Cortana replied. "I did get a data purge reading from when it teleported. That one was a "Promethean Knight", if I'm getting it correct."

"More of them!" Twilight yelled, seeing multiple Knights and Crawlers battling a platoon of Covenant. Chief readied his Assault Rifle, but Twilight held him back.

"I've got an idea." she said, flaring her horn for a teleportation. The two of them appeared across the battlefield, out of eyesight.

"Neat." Cortana said. "Your kind can teleport?"

"Unicorns like myself can." Twilight said. "It's highly advanced magic."

"Remember to tell me about that later." Cortana said. "Magic...that's fascinating!"

"Can it wait?" Chief said as they entered the room where Infinity's broadcasts were originating from. "I've got a bad feeling about this."

"Same here." Twilight said, illuminating her horn for a light source. "This doesn't look good."

They entered the chamber, and Twilight's attention was drawn to the multiple Prometheans guarding a large orb in the center.

"That orb's generating the field that's cutting our comms with Infinity." Cortana said. "There's no sneaking around this time."

"Right." Twilight said. "On you, Chief."

Chief dove into view and opened fire, Twilight growling while picking up and throwing a Knight into the abyss.

====

"WHAT!?"

Celestia's mane flared with fire as she stared angrily at Pious Deacon and Luna, both of whom flinched.

"Please do not be angry, Ascendant One!" Deacon said. "I merely confirmed that your counterpart is correct. A slipspace rupture did occur at this location as a result of a failed energy surge."

"And where did that surge take Twilight?" Shining Armor asked.

"Unfortunately, I don't know." Deacon said. "That rupture sent this "Twilight" far beyond the range of my scanners. The closest I can guess is the Requiem Installation, exactly 126.91 Light Years away. And seeing as your kind has not developed a Slipspace-capable vessel, you are stuck here."

"Tartarus." Celestia cursed. "What now? How can we get to her?"

"Unknown." Deacon said. "I do not have any slipspace-capable constructs, and I believe a second energy surge would not be favorable."

"Why?" Rarity asked, raising an eyebrow.

"Slipspace is a highly unstable method of travel." Deacon replied. "A single miscalculation could send the subject straight into a star or black hole. Furthermore, Requiem is a highly dangerous installation. It is the resting place of one of my creators, who was exiled long ago."

"Who is this creator?" Luna asked.

"The Ur-Didact, of course." Deacon said. "He is the Supreme Commander of the Forerunner Military, and Protector of the Ecumene. He is a formidable warrior, and not to be trifled with lightly. There is nothing I can do to help recover your friend, for that I am gravely sorry."

"It's fine, Deacon." Cadance said. "Right now, I need time. Deacon, what happened to Queen Chrysalis?"

"She is being kept in stasis below ground." Deacon said.

"Take us to her." Celestia said. "I need to have some words with her."

"As you wish." Deacon said.

====

Author's Note

Sorry that it's so short. And sorry this took so fucking long.

More frequent updates are coming soon!