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The Parallel: A Halo AU

Halo AU. Really, REALLY AU. "We exist together now; two corpses... in one grave." If you were taken from your home and made into a monster, would you break... or would you fight? Master Chief x Cortana Words in total: 251 909 ************************* Disclaimer: I do not own anything ************************* Original Author: https://www.fanfiction.net/u/765180/Kireteiru

CopyPaperMan · Video Games
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79 Chs

Two: Requiem

When the Chief woke, they were on the inner surface of Requiem. His entire body was screaming at him to stay where he was. He listened to it only long enough for the ache of the crash to fade. Then he struggled to get his body to respond to his commands.

Cortana had activated the suit's basic first aid, which included painkillers, so at last, he was able to get his fingers to twitch, then curl into a fist. There was debris on top of him, restricting his movement – he pushed it off. He sat up and looked around. They were surrounded by the burning remains of both the Dawn and the Covenant's battle cruisers, broken hulls and gear scattered for miles around. The Spartan groped for a nearby weapon, then pushed himself up onto one knee.

Cortana was ominously silent in his helmet, but he could still feel the warmth of her presence. "Where are we?" he asked lowly.

Her voice was tired. "Checking coordinate impact data – we have asked you to give up your family, your childhood, your future-"

John tensed when he heard the distorted recording of Doctor Halsey. He shook his head in an attempt to clear it, then reached back and pulled out his AI's chip. "Cortana!"

Her hologram appeared over the chip in a flare of light. "I'm sorry," she apologized, hastening to reassure him, "It's the crash, I'm fine."

"Something was wrong even before we left the Dawn." That was putting both things lightly. 'Please, no.' An exercise in futility. He knew exactly what was wrong with her – the same thing that had been wrong There.

"Chief, really. I'm fine." That might have been enough to convince him if her voice hadn't come out distorted again.

He got to his feet without taking his eyes off her. "Cortana," he said, gentle but firm.

The AI's gaze dropped to her feet. She drew small circles in the air with her toes. "I was put into service eight years ago."

His heart rate jumped. "Eight years…"

She looked up at him. "AIs deteriorate after seven, Chief."

'Goddesses damnit no why couldn't I have been wrong – they aren't here to help me stabilize her – this can't be our last mission I won't let it be-' "Halsey," he said, the idea forming in his mind even as he spoke.

"Chief-"

"We need to find Halsey."

"Chief, please!"

He depolarized his visor so he could look her in the eye. "She made you," he declared, "She can fix you." 'She damn well better be able to…'

"I won't recover from Rampancy, Chief."

She looked as if she was trying to accept it herself even as she said it to him. The Spartan resisted the urge to :reach out: to her, didn't even know if he still could. "If we can just get back to Earth, and find Halsey," he told her, "she can fix this."

Cortana looked up at him in silence, seeing the strength of his conviction in his eyes. Then she said, "Don't make a girl a promise you can't keep."

A pair of Phantoms zipped overhead, ruining their moment. "We need to move!" the AI called, then vanished in a flare of light. John inserted her chip into his helmet once more. As he moved down a short slope and further into the wreckage, she said, "It doesn't look like the Covenant fared much better than we did."

"How many ships made it through the roof?"

"Plenty… why?"

"We still need a ride home." The super soldier picked his way through the wreckage, picking up a few undetonated grenades and more ammunition as he went, checking it all over to make sure it was undamaged and still worked.

There was a crevice in the rock on the far side of the canyon. He proceeded through it at half pace, tense and ready for combat. He almost fired off a shot when Cortana spoke. "I'm picking up a faint transmission on the high-band," she reported, displaying the waves off to one side on his HUD.

"Covenant?" John asked as he kept moving.

"I don't think so," she replied, "the pattern's different. I'll try to triangulate its position."

He wanted to tell her to ignore the transmission and focus on finding them a way back to Earth. Instead he stayed silent, intent on keeping his footing as the ground started to slope drastically upward. The light of Requiem's false sun made it impossible to see what he was making his way toward, but his motion tracker showed no contacts.

They emerged onto a right overlooking an enormous power complex, a trine of pylons floating over their housings and gathering energy from space itself. He took a moment to admire the architecture, the technology inside, the painstaking research and precision that went into constructions like it. Then he moved on, following the ridge as it curved away.

The wreckage of a hangar bay had crumpled and fragmented against the unforgiving stone, letting its contents spill out. Warthogs were strewn about like toys in the grass. Most were broken, some on fire, but there were two or three in relatively good condition. The Spartan mounted up and got moving.

As he rounded a curve, Cortana began speaking, "Chief… about my 'condition…'" When he lifted his chin to show that he was listening, she continued, "I didn't want to mention it, seeing as how it's a complete long shot, but since you brought it up… it is possible that getting home could help me find a solution for my Rampancy."

"How?"

"Well, as far as I know, I'm the only AI ever generated from living tissue – a clone of Dr. Halsey, to be precise. It may be possible to recompile my neural net by replicating those same conditions. But that means getting back to Halsey. Soon."

John guided the LRV through the wreckage of the Dawn. They drove in silence for a time, then Cortana spoke again. "Chief, I'm hearing that strange signal again, stronger this time."

"Do you think there's something to it?"

"I'm curious more than anything. Its behavior is… odd."

The Spartan stopped the Warthog on the edge of a wide grassy canyon. The Covenant had already set up towers and barricades at various points amongst the spurs of rock. A Phantom was dropping off its load of soldiers to his left on a stretch of clear ground.

The Chief hopped out of the driver's seat and got behind the machine gun turret instead, opening up after the Phantom zoomed off. The Jackals and Elite went down fairly quickly, but then one of the Grunts hopped into a Ghost and came skittering towards him. Despite the notorious inaccuracy of the machine gun turret, he was able to kill the Grunt without doing too much damage to the other vehicle. He bailed out of the Warthog in favor of the Ghost and zipped around on it, both shooting and ramming the aliens with justified malice.

As he was about to leave the Ghost behind and move one, he noticed the orientation of the ramp and grav lift of the tower that he had shot down. It was right before the ridge that was stopping him from continuing on in the Covenant vehicle. It looked like if he used the Ghost's boost, he could get enough forward momentum and upward motion from the grav lift to clear the ridge and continue on without having to go on foot.

"What are you doing?" Cortana demanded as he moved the Ghost into position.

"Bringing this with us."

"Why?"

He raised an eyebrow. "Increased mobility and speed, superior firepower, the element of surprise…"

"Ooookay."

John hit the boost. The Ghost shot up the ramp and was caught by the grav lift. It tumbled once in the air, but cleared the lip with room to spare. The Spartan allowed himself a small smirk before he moved on, gunning down a trio of Grunts who had obviously come to investigate the commotion.

"If we're going to hijack a ship from these Covenant, we're going to have to find out where they're landing first," Cortana stated as John boosted over another small ledge.

"I don't suppose you have a plan for that?"

"We could always ask nicely."

"'Asking's' not my strong suit."

As if to prove his point, the Spartan gunned down the Covenant forces in the canyon that their crevice-pathway opened up to. There was a Forerunner structure on the far side that the Covenant – these "Storm Covenant" – were holding. He killed them, too, along with the Zealot who led them.

"That Elite dropped his camo module. Let's have a look."

John dismounted from the Ghost to pick it up.

"I'll run a patch with your suit's firmware. Who knows – it might come in handy."

"Thank you," said the Spartan, "I'm sure I'll enjoy being able to invisibly slay my enemies." His lips twitched into a tiny smile when he heard Cortana snort.

The massive door at the back slid open as he climbed back onto his Ghost. As he steered it inside, the AI brought up another wave display. "There's that phantom signal again."

John paused to listen. "I heard something that time."

The signal faded away. The inner door slid open, and John guided the Ghost into the chamber beyond. Then he started, involuntarily sending the Covenant LRV jerking backwards. "Sentinels."

"I wondered when they'd show up."

The machines weren't attacking, but he had every reason to be wary of them. With Spark, they had just been doing their job, but it had shown him how easy it was for rogue Forerunner AI to add "Reclaimers" to the local Sentinels' targeting roster.

For the moment at least, they seemed content to guide him to the control panel at the back of the chamber. He touched the interface, and a holographic sphere flickered to life overhead. "It's a localized site Cartographer," Cortana informed him, "Hm… Okay – 'in service of Forerunner Shield World designate Requiem.'"

'Shit.' "Requiem. At least we know where we are now."

"Let's see if it can tell us what the Covenant are so interested in." When the AI tried to access the information, the hologram turned red, flickered, and disappeared. Yet as it flashed, the Spartan caught a glimpse of a familiar symbol, and felt dread drag his stomach down like a lead weight.

'Double shit.'

"Huh."

"What happened?"

"I don't know… It locked up."

'Triple shit.' The Spartan turned around to go back to his Ghost, only to find that it was no longer there. He glared up at the Sentinels innocently orbiting the Cartographer, then pulled out the SAW that he picked up in the Dawn's wreckage. The Chief jumped down from the map platform, and began walking back the way they came, when he noticed a ramp leading down below the central "spine" of the room.

He ducked down into it, and spotted a massive metal Forerunner sigil against one wall – the Eld of the Mantle of Responsibility. As he got closer to it, he saw that there were glyphs inscribed on the symbol.

And he could read them.

"'Guardianship for all living things lies with those whose evolution is the most complete,'" he read aloud, "'The Mantle of Responsibility shelters all.'"

"John…" Cortana sounded as shocked as he felt. "How…?"

"I don't know," he said finally. Maybe… maybe… it wasn't just a dream…?

"Hm. In any case, this is very interesting."

"Maybe," he replied, "but it won't get us home." With no further information forthcoming from the Mantle symbol, he headed back up to the main floor.

"I'm detecting power fluctuations in several locations," Cortana said after a moment, "I'll put them up for you." A pair of orange nav points appeared on his HUD. "Hopefully we can find some way to get this Cartographer back online."

John moved toward the closest of the nav points. He recoiled when more Sentinels glided out of the side chamber right in front of him, but again, they did not attack. He waited until they were far enough away to be comfortable before he turned his back to them.

In front of him was a simple enough console: a thin black rectangle perpendicular to the floor with a large green button in the center. He pushed the button and extended the light bridge, walking across it to the power core. The Spartan reactivated it, but as he did so, his shields dropped to zero, the alarm beeping, and the platform under his feet began to drop.

Purely out of reflex, he turned and jumped back up onto the light bridge, lifting his SAW. "What's it doing?" he demanded, tense.

"It's alright," Cortana assured him. After a momentary pause, she continued, "This energy is actually a ferroelectric data field. Your shields are just cycling in response to the chamber's charge."

The warrior relaxed a little. "Will this bring the Cartographer back online?"

"Partially," the AI answered, "This type of processing system usually works in parallel. We'll have to locate its twin."

The Chief left the power core behind, but not before he peered over the edge. The platform had simply descended to a lower level, but even so, he hadn't liked getting caught off-guard by it. He was about to reenter the main chamber when his motion tracker flashed red with hostile contacts. Some Covenant had found a way inside. John crouched and switched his SAW for his battle rifle, then crept forward a bit at a time. A handful of Elites, a similar number of Jackals, and a small swarm of Grunts were now in the central chamber. The Spartan activated his new handy-dandy active camouflage and began picking them all off one by one, backing up when the time ran out and he decloaked. After a few minutes, all of the aliens he'd managed to coax out of hiding were carpeting the floor of the chamber. He hopped down from his perch to pursue the others.

During the ensuing firefight, his BR ran out of ammunition, so he dropped it in favor of a carbine he found on the ground. It still worked, so he took it. He reasoned that he was far more likely to find ammo for it than either of his human weapons.

The Spartan headed across the room to activate another light bridge, then the second data field. Again, he jumped back onto the first bridge rather than descend to the lower level. As he walked back along the bridge to the main chamber, a set of signal waves popped up again. "Is that the same signal?" he asked his AI. For a second, he distinctly heard a male voice say, "FLEETCOM actual," and "UNSC survivor 883."

"Yes!" Cortana crowed, "Mayday, mayday, mayday! UNSC AI Cortana to Infinity, please respond!"

There were more Covenant in the chamber. As the Chief started shooting, he heard FLEETCOM respond to the Infinity, who apparently hadn't received Cortana's transmission. "No response," the AI reported, "but from the strength of that signal, the Infinity has to be close by!"

It took him twice as long to clear the room, mostly because there were twice as many enemies. He nailed as many of them as he could from afar with the carbine, then once again switched back to his SAW for the up close and personal battles. At last, he made his way back to the Cartographer. He slotted Cortana's cartridge into the map's interface.

Cortana appeared on the holodisplay, along with the image of Requiem. When she reached out to interact with the display, it flickered red again before returning to normal. She shook her head and spun the dial, interacting with the map. A number of red tags appeared around the hologram of Requiem. "The Cartographer keeps acting like the transmission is coming from everywhere on the planet at once," she told her Spartan, "It doesn't want to triangulate Infinity's signal."

The hologram flickered again, and all but one of the red tags disappeared. The tag was at the core of the planet.

The hair all over the Spartans' body stood on end. 'The Didact. Is he trying to manipulate us into releasing him?' His skin crawled, akin to the prelude of his Flood-based shape shifting, but no such contortions took place.

"I got it!"

"That can't be right. Scan again."

But the Forerunner's Cryptum did have a broadcast relay that would have enabled him to access the Domain, if it had survived the firing of the Halos. Perhaps there was some way Cortana could circumvent the unlocking sequence.

"We've already passed through one layer of the planet's surface," the AI answered, "It's not crazy to think that someone else made it deeper inside than we did."

"You mean the planet's hollow?"

Cortana seemed to understand his "confusion." "Let me see if I can figure out a way for us to reach these coordinates that doesn't involve us digging a really big hole." A new map, long and thin, popped up at about head level. "There's a Terminus on the far side of the complex," Cortana said, turning to look at him, "We can portal to the planet's core from there." She shot a glance back at the hologram.

"What?"

"…I don't know."

John made an executive decision, then; Cortana was a valuable resource for the UNSC, but first and foremost, she was a good friend to him, the only one he was sure was still alive. Getting her to safety surpassed the danger of the Didact on his personal priority scale. "If we have a shot at getting you back to Infinity, we're taking it." When she assented, he reclaimed her chip and turned to head deeper into the complex. Yet as he walked away, he heard the Cartographer glitch again behind him.

"What do you know about Infinity?" he asked the AI.

"Not much. She was supposed to be massive, but the project was only in prototype when we left."

The Spartan exited a short hall into a large underground cavern. Or, formerly underground; part of the ceiling had crumbled onto the bridge spanning the chasm, letting sunlight in. It had also let in several Phantoms' worth of Storm Covenant.

The warrior fought his way across the first half of the bridge, slaying the enemy aliens who crossed his path. The array of combatants was fairly standard, nothing to sneeze at, but nothing to get worked up over, either.

There was a Banshee on the upper level of the main bridge, just a short ways across a lower, smaller bridge – a choke point. There were some Grunts, a few Jackals, and a pair of Elites on the other side. The Chief took out the Jackal sniper first, then the Sangheili, then the other Covenant, even going so far as to punt one of the Kig Yar off the edge to conserve ammo. Then he took to the skies in the Banshee, rolling to avoid fire from the other aircraft.

The Spartan switched to the fuel rod gun and blasted one Banshee apart right away, then switched back and pursued the other, careful to keep himself out of range of fire from the bridge below. When the second Banshee went the way of its predecessor, he turned his fire on the ground troops, hitting the Elites with fuel rod charges. One of them managed to dodge the initial blast, but misjudged his leap and the distance the blast would push him. He wound up flinging himself off the edge of the bridge.

John let out a quiet huff of laughter, then moved to strafe the remaining aliens. They died under a hail of plasma, leaving him free to set the ship down on the far end of the bridge. As another massive door slid open at his approach, Cortana piped up, "Chief, the Covenant net's going crazy. They're ordering all units to converge on the tower."

"I guess we got their attention." The Spartan walked to the other end of the hall and waited for another door to open in front of him, taking up his carbine as the light spilled in.

A Phantom had just dropped off a number of Unggoy near the door. The Chief picked them off quickly, but the gunfire drew the attention of the other Covenant in the area. Two Ghosts came zipping around the processional way leading up toward the tower. Through a stroke of his usual incredible luck, he managed to kill one of the Grunt pilots before the alien even fired a shot, then crouched and let the other Ghost's shots fly over him. When the firing stopped, he peeked up, took aim, and fired off five shots, the last of which connected and sent the Grunt sprawling to the ground, its Ghost moving an additional few feet before shutting down.

There was some UNSC ammunition scattered around the canyon when he emerged into the light. The Chief stocked up, and took out the Grunt manning the Shade turret set up nearby. He sprinted back to one of the Ghosts and claimed it for his own, bringing its guns to bear on the other Covenant running around on the processional way, then the ones taking cover on the observation decks on either side of the path.

The tower and the path leading up to it were meant to mirror the Spire and its processional way in the Forerunner Capital, which in turn mirrored the Tower of Eternity (which wasn't actually a tower at all). Though he was not religious himself, the Spartan understood why the Forerunners would want to have a part of their symbolic path of enlightenment inside their Shield Worlds. He was also angry at the Covenant on their behalf for turning their equivalent of a church into a warzone. They worshipped the Forerunners – they should have been more respectful of their constructs.

John gunned his way to the lift in the tower, clearing out all of the Covenant in his path, even the Hunters that were deployed in the aliens' attempt to take the tower before he could. He put away his weapon the moment the area was clear, and entered the Cathedral. Massive machine panels retracted in pairs as he approached, opening up the space inside, then slid back into place as one when the lift carried him up.

The Cathedral was lit with a low blue light as he walked the rail-less path up to the Terminus interface. There were a number of low, square pillars on either side of the path, ripples of light travelling up their lengths to illuminate the sigils on their sides in a momentary flash.

When he inserted Cortana into the system, the Cathedral came alive, portal anchors snapping together, suspended in the air. "According to the Cathedral, this Terminus is just one node in a large transit grid that spans the entire planet…" She trailed off.

"What?"

"When I tried to access the outlet closest to Infinity's transmissions," the Ai answered, opening the console, "the system responded with this."

A symbol appeared, one he knew well. No matter the changes wrought in him or how monstrous he became in battles he fought in the Parallel, that symbol was always engraved into his armor, integrated into his own personal sigil. "Reclaimer," he said, "humanity." Though he was hesitant to move forward, wary of the Didact's manipulations, the Spartan knew he had no choice if he wanted to save his AI. "That's got to be Infinity. Can you get us to those coordinates?"

"Let me try to open a portal." Cortana interacted with the display, the Terminus shifting as it heeded her commands. There was a thunderous clank, and the pillars began to rise with the Terminus platform. "I'm picking up unknown energy signatures!"

"Where?" He could sense something, too, but the Spartan didn't have her precision any longer.

"This can't be right!"

And then Promethean Knights, blue-accented, began materializing on the plinths, their insect-like carapaces fluttering like wings to vent heat.

"Set a waypoint out of the tower." John knew that Cortana was struggling with the Terminus, but he couldn't save her if she was destroyed before they reached the Infinity. Her safety was his top priority. They had to get out. "Cortana?"

A portal swirled open. "How did…" But like him, Cortana wasn't about to look a gift horse in the mouth. "Quick! Into the portal!"

Without thinking about who created it or where it led, John snatched her chip from the system, then turned and flung himself into the vortex.