Disclaimer: Don't own FFXV

I've read a bunch of ones were Prompto gets de-aged so decided to give it a go.

Chapter 1

Noctis released his sword back to the Armiger with a sigh of relief, muscles aching in a familiar way that meant he was on the edge of stasis. He looked around to see Ignis forcing a potion on Gladio and….Prompto dropping down from the catwalk he'd ended up to escape a swarm of MT's, shooting them from a distance. He was limping, a bruise already visible along his jaw and Noctis staggered over, breaking a potion over him.

"Thanks buddy," Prom grinned and then slipped under his arm, letting Noctis lean on him as they walked over to the others.

Ignis took one look at him and pushed an Ether into his hand, making Noct grimace in distaste but he obediently broke the bottle. He understood the necessity, they were in the middle of a new Imperial base and while they seemed to have cleared it, there was still a chance they would end up in combat again.

"Anyone else think this base is weird?" Prompto asked and Ignis nodded, pushing his glasses up.

"Indeed, the layout appears quite different to the others we have attacked and the troops here were stronger."

"Great, just what we need," Noctis grumbled. The average MT was easy enough to deal with but stronger ones, especially if they became common, could be a problem.

"We should check to make sure we got everyone and see what intel we can gather for the Marshal while here," Ignis suggested and while all Noct wanted was to collapse on a bed he knew Ignis was right.

They split into pairs and began combing the base for clues as to what the Empire had been up to. Noct grabbed Prompto and they headed further into the base, ensuring one member of the pair could at least read Gralean to translate anything they found. Iggy had learnt as his Adviser and Noctis had learnt because it was expected of the future King to know as many of the worlds languages as possible. It wasn't his best language, but he could manage.

"This place gives me the creeps," Prompto admitted as they searched, the muted light making it harder, but they'd taken out the Magitek generator immediately, so the base was operating on low power.

He answered his phone when it rang, listening to Ignis. "Right, be careful too," he told him before hanging up.

"What's up?" Prompto glanced over from where he'd been checking in some lockers, finding some personal belongings but nothing else.

"They found some mentions of Solheim tech, so Iggy was just warning us to be careful."

"Like those weird ruins kind of tech?" Prompto looked at him and Noctis nodded. "Great, last thing we probably want them messing with."

They left the staffroom and headed down the hall quietly, Prompto with gun in hand in case anyone was left. Noctis was still feeling a little tired from the fight and would summon a blade as soon as he needed it.

They came to a secure door and Noctis used the stolen access card, Prompto covering him. Noct opened it and moved through only to freeze with wide eyes as he stared at…something. Prompto moved in behind him and whistled softly in shock. It was…massive and creepy and like nothing either had seen before.

"How'd they get that here without anyone seeing?" Prompto asked.

Noctis moved to the railing and looked down. "I don't think they did…I think they excavated it here and built the base around it." he pulled out his phone and called Ignis to let him know what they'd found.

"Looks all the equipment's on the bottom level," Prompto pointed, leaning over the railing slightly.

"Want to take the quick way?" Noct asked with a grin and Prompto shook his head, backing away from the edge.

"No way dude, you're too close to stasis still. Let's find the elevator," he dodged around Noctis to find one and Noctis grinned but followed.

They went to the central staircase rather than leave the main chamber to look for an elevator, heading down the metal stairs as quietly as they could but the place was as quiet as a tomb. The thing was at least thirty stories high, extending far underground which was why he thought it had been excavated. Still, they should have heard something, it would have taken months with heavy equipment if not years. Thankfully, they hadn't been on the top level when starting.

"That's a lot of computers and consoles," Prompto offered when they made it into the massive room at the bottom of the artefact.

"Look but don't touch," Noct warned, moving to see what the Empire had learnt from it.

,,,,,,,,,,,,,,,,,,,

Prompto looked around, seeing all of the monitors, machinery…all of it leading back to the machine in the middle. He wanted to look things over himself but…no one knew he knew Gralean, it would contradict the lie he'd lived ever since being brought to Insomnia.

He'd considered telling them, or at least Noct, a few times over the years, especially once the peace treaty had been announced. After Insomnia had fallen he knew that he could never tell them the truth, there was too much personal hatred for the Empire now and MT's especially. If they ever found out he'd lose everything, he'd be lucky if they executed him. The thought of them looking at him like they did other MT's…of seeing hatred and worse aimed his way, it made him feel sick.

"Anything interesting?" he forced himself to ask as he wandered around, double checking they were alone again.

"The Empire's really interested in this thing," Noct answered absently, going through some files.

"So we blow it?" Explosions could be fu

"That'll be one big boom, too dangerous," Noctis shrugged and Prompto nodded, he had a point.

Out of Noctis' sight he looked things over himself, recognising the shorthand used by Niff scientists despite the years.

"Huh."

He looked up and made his way back towards Noct. "What?"

"They've been working on translating writings found around here. Didn't know anyone could read Solheim anymore."

Considering the whole time period was considered a bit taboo back in Insomnia due to the Astral War… "Maybe the Empire never pushed people from investigating it?" he offered. Wasn't Magitek old Solheim tech or something so they obviously were able to work some of the dead society out. "Have they managed anything?" he leant closer.

"Looks like…youth? No…maybe…slipping? Back? Whoever wrote this must have been working on no sleep and a caffeine high," he complained and Prompto chuckled.

He looked at the file and agreed with Noct, even if he couldn't understand what was written, the handwriting was horrendous. "Aren't doctors meant to have sucky writing? Maybe scientists count?" he suggested and Noctis laughed.

"Why not," he agreed.

Leaving Noct to it, he pulled out his phone to check where the others were, happy to hear they were on their way down, it was just taking a while since they had yet to find access to the central chamber, the base was a labyrinth probably to keep Lucians out.

Of course, that was when a familiar sound filled the air and Prompto rushed back to Noct's side to find him summoning his sword, facing off against three MA-X Maniple that had been released from somewhere.

"What did you touch?" he demanded as he summoned his other gun and opened fire.

"Nothing!" Noctis denied, warping up to strike at the missile launchers since they were the main long range weapon on the thing. With them out of the way they could stay out of range and wear the things down.

Prompto stayed under cover as best he could, focusing on one at a time, wishing he had something more powerful like a rifle, he really needed to steal one while they were on the base. He hated leaving Noct out in the open alone, but he couldn't warp away from bullets like his best friend could. He really wished the others weren't still a few levels away! He glanced around and spotted a crate suspended above them, judging the angles.

"NOCT CLEAR!" he yelled and Noctis warped well away even as he opened fire. The chains shuddered under a hail of bullets and then they snapped, dropping the massive shipping crate right down on two of the machines, leaving just one for them to deal with and it's launcher was hanging by a thread.

"Nice work!" Noct grinned at him and then warped after it, slashing at its 'ankles', trying to make it fall.

Prompto aimed at various joints to try and disable the various weapons attached to them. He glanced back and grimaced, they were getting way too close to the Solheim thing for his liking. The crate had taken out the two armors, but it had also cut down on their room to manoeuvre. He let out a strangled gasp as agony exploded through his left arm, hearing the gun drop and return to the Armiger, his fingers limp. He staggered back, away from the spray of bullets.

"Prom?" Noctis yelled in alarm and then he was there, breaking a potion over him.

"Thanks," he panted as the pain faded and he regained feeling in his hand, resummoning the gun. He really needed to get better at summoning things, he couldn't keep relying on Noct and Iggy. Something to work on when they weren't being shot at.

"Okay?" Noctis asked and Prompto grimaced.

"Use an Ether or Elixir, you're too pale," he warned, turning and firing to keep it busy while Noctis did as told. It wasn't good to use too many of those things, he needed sleep and food, but there wasn't time until they were done with the base. Who knew how long it would take the Empire to send forces to retake it.

Noct tossed a lightning flask and Prompto pulled out his circular saw, dashing in while it was off balance. The saw cut deep into the armor and it toppled over, giving him access to various control panels which he cut through as quickly as possible, severing vital connections and it spasmed wildly before deactivating.

"Well…that was fun," he panted, grinning as Noctis staggered over and dropped down beside him.

"Fun?" he bumped shoulders with Prompto and then summoned potions to finish healing their various injuries. "You need a better idea of fun," he grumbled.

Prompto chuckled tiredly and then grimaced as he caught a whiff of them both. "Eww…we stink." Not just drying sweat but the various mechanical fluids from the armors too, on top of the previous fighting. "Think Iggy'll agree to spring for at least a caravan?"

"With how bad we stink? He better." Noct groaned but got up and Prompto scrambled up as well. "Better call and let them know we're okay, no way they didn't hear or feel something of that."

"I've got it," he pulled out his phone so Noctis went back to looking over the files.

He eventually had the guys reassured that they were fine, able to hear them running over the phone. He hung up and this time stuck closer to Noctis, keeping one gun out and ready for anything else the place could throw at them. So when he saw an ominous red glow from behind Noctis he was moving before he really registered anything.

"DOWN!" he slammed into Noctis, shoving him aside and then everything went red.

,,,,,,,,,,,,,,,

Noctis frowned, trying to decipher the notes. While blowing the place sky high sounded good, who knew what that would do to the artefact. It might just rebury it or it could cause it to explode and take out half the continent. Maybe fill the base with cement? But that would take forever even with an army, something they were sorely lacking. He would be happier when Ignis and Gladio reached them, it'd be good to be able to split the translation work.

They really needed to work on teaching Prom and Gladio the language for such situations. They should all go over the military procedures that Noct had been drilled on too, Ignis and Prompto could go undercover as long as they both knew the language. Noctis was too well known without access to the various methods of disguise that had been available in the city. Ulldor proved that not all who worked for the Empire had light hair so he wouldn't have to die his hair, but his features would need disguising.

"DOWN!"

He felt Prom slam into him, sending him tumbling to the side and he winced as bright red light flashed through the room. There was nothing, just the light, and Noctis scrambled up. "What was that?" he asked, moving back around the bench and then he froze, jaw literally dropping open in shock. "Prom?" he whispered and wide blue/violet eyes locked on him, the gun coming up to aim steadily at him.

Was this really Prompto? But he was wearing Prompto's clothes, well, more like swimming in them. He was tiny, not even four and a half feet tall from what he could see. His hair was shorn short, a yellow bruise along his right cheek which had Noctis wanting to summon a potion, but the injury was likely too old for it to do anything. Small hands were utterly lost in gloves that were now massive, going almost all the way up to his elbows. He was sitting on the ground, aiming the gun right at Noctis who raised empty hands and then was hit with another shock.

"Identify yourself," the child demanded in perfect Gralean.

TBC…