MLPU: The Invincible Iron Mare

by TheInvincibleIronBrony


Rainbow and Comet had gotten up bright and early to begin working on the armor. Of course, in the dankness of the cave, it was hard to tell the time of day, so most of the time, they simply made due with guessing the time. Rainbow busied herself shaping a piece metal into a chestplate, while on the table across from her, Comet prepped an empty mortar shell to act as a fuel tank.

Rainbow sighed in satisfaction as she finished hammering the right curve into the metal plate. She set it with a few others on a table in a small pile. Her father had insisted that they make the chest plate in pieces, both to avoid suspicion, and so that when the time came, they could weld them together. They had to be careful of what they were doing, due to the camera high up on the wall in the back left corner.

Rainbow's eyes scanned the table for the next project to keep her mind occupied. If there was one thing Rainbow hated more than anything else, it was boredom. She cast a quick glance towards her father, who was still absorbed in his own task, as the characteristic glow of magic and sounds of tools being employed seemed to indicate.

Figures he'd be distracted, She thought grumpily, turning back to the table and starting to gather the materials she knew would be needed to allow the ARC Reactor to power the hydraulics in the suit's legs and arms. She held her hand out for a few seconds reflexively, expecting to have the correct tool to be laid in her hand, ready for use. When the tool didn't appear in her hand, she looked to her left in frustration. She expected to see Caramel, who usually stood at the ready to help her back at home. The sight of a cave wall only managed to remind her of her current state. Right...I’m not at home, she told herself sadly, turning back to her work. As she worked, she was reminded of how much she actually needed an assistant, since actively reaching for tools and not having them instantaneously handed to her hadn’t been a real problem for quite awhile. Especially when she first got T.A.N.K. up and running.

“Yeah...I could do with some help from T.A.N.K. right now,” she muttered, turning the wrench and thinking back to the time she first got her computerized friend.


“So what is it?” Caramel asked, looking at the computer screen over Rainbow’s shoulder.

Rainbow let out a content sigh and leaned back, a proud look on her face. “It’s a digital assistant,” she answered, turning to face Caramel, who now had a slightly worried expression. “Don’t worry I’m not replacing you. This is just to help me run simulations on new tech as I build it,” she explained, patting him on the shoulder as she got up from her seat.

“You spent two weeks programming a computer and at least three dozens robots to make a digital me?” he asked, following her. Rainbow shook her head.

“No. It’s supposed to help me with making my designs and such. Celestia knows I need someone who can help me whenever I need them,” Rainbow replied as she walked to the other side of the room.

“Alright then, if you say so. Got a name for it?” Caramel asked, raising an eyebrow.

Rainbow paused, putting a hand to her chin for a moment. “’s a...Technology Application Network... Knickknack,” she answered, trailing off at the end.

Caramel smirked slightly. “Did you really want it to spell T.A.N.K. that badly?” he asked teasingly.

Rainbow simply gave Caramel her own smirk in response. “Oh come on Caramel, you know that’s an awesome name,” she said, internally acknowledging the lame name. The sound of her stomach growling. “Hey, you wanna get pizza or something?” she asked, desperate to change the subject. Caramel shrugged.

“Yeah I guess,” Caramel agreed, trying not to chuckle.

“Awesome!” Rainbow said, starting up the stairs, with Caramel close behind, an amused smile on his face.


“RAINBOW!” Rainbow jumped at the sound of her name, snapping her out of her memories. “We can’t afford to get distracted right now. Get back to work,” her father ordered her from across the room before the sound of tools and magic started up again, returning to whatever it was he was doing.

“Yeah I know,” she shot back, more embarrassed that she’d been caught daydreaming than anything else.

“If you did know that, then you wouldn’t be wasting time spacing out over there,” he replied, the sound of a hammer loudly strike some metal for emphasis.

“Oh, I’m sorry I’m not completely focused, being held hostage. This isn’t exactly a night at the club for me,” Rainbow replied, her voice dripping with sarcasm. “Where I’d much rather be if it were up to me...”

“Trust me, if it were up to you, you’d just be picking out a stallion for a one night stand,” Comet replied, still focused on his work.

Rainbow practically bristled at this and found herself reaching for a wrench to throw at him, but held herself back. “You know what,” she said, her anger barely held in check as she dropped the wrench. “We’re wasting time sniping at each other. How about we just finish this and we can get back to avoiding one another once we’re out?” she grumbled, still trying to keep from exploding in anger.

“Okay,” came Comet’s unexpectedly calm response. Rainbow turned to see him staring at her as if she sprouted a second head.

“Uh...alright then,” Rainbow said awkwardly. She hadn’t expected him to agree so quickly. Then again he probably hadn’t expected her to say anything remotely responsible. They both went back to work, an incredibly awkward silence falling between them.

Rainbow decided to return to work and started twisting a bolt into place with a socket wrench. Once it was tight enough she attempted to pull the wrench off only to find that it was stuck. She grabbed the tool in her teeth and pulled as hard as she could, muttering and grumbling under her breath. The wrench all of a sudden popped off of the bolt and sent Rainbow tumbling over backwards and onto her back.

She looked up to see her father staring at her. “If you use a wrench a size bigger than the bolt it should still be able to grip the bolt without getting stuck,” he suggested, as he used his magic to help her up.

“Uh... thanks,” Rainbow replied awkwardly as she was pulled off of the ground. Comet simply nodded and returned to his work as Rainbow turned back to the device she’d been working on. She grabbed the wrench she’d just used and looked at it for a second. After a moment of consideration she put it back with the other tools and grabbed a slightly larger one. She started twisting the next bolt in. Once it was tight enough she pulled on the wrench and found it came off much easier than the previous one.

Rainbow looked over her shoulder at her father. He still seemed like he was more focused on his work than anything else. This was the first time he’d done anything fatherly. Rainbow smiled at the thought before shrugging and returning to her own work.


The pair of captives had stopped for a lunch break when their captors brought what appeared to be brown slop. Rainbow was poking hers with a spoon.

“Don’t be childish, just eat it,” Comet said from his spot across from her at the table and took a bite of his own slop, visibly grimacing at the taste.

“And you’re telling me not to be childish,” Rainbow replied smugly, a smile forming on her face.

“At least I’m eating. Come on now, we’ll need our strength,” Comet replied.

“And what pray tell do you need to keep your strength up for?” A voice said from the door. Both Rainbow and Comet looked to see the terrorist leader, standing in front of the closed doors.

Rainbow and Comet’s eyes went wide. I didn’t even hear the door open, Rainbow thought.

“For building your weapons,” Comet answered, quickly recovering his composure. “Can’t build on an empty stomach,” he explained.

“Of course, how silly of me,” the stallion said, not sounding amused at all. He walked over to their table glancing at the food as he stopped near them. “And how goes your progress?”

“We’re moving along. We came up with a new power source for anything else we make,” Comet said, pointing at the reactor in Rainbow’s chest. “Rainbow wanted to test it with her magnet before we put it in anything explosive,” Comet explained. Their captor looked at the soft glowing machine and then at Rainbow.

“I may not live for much longer, but I’m willing to try anything that’ll put the suffering off for a little longer,” Rainbow said, hoping he wouldn’t inspect the device itself.

“Very well. When you have finished eating, return to work. I’d like results within the week,” he said as he made his way over to the door. Rainbow and Comet looked at each other in relief. They turned back towards the door to see that their captor had seemingly disappeared.

“Seriously, how does he do that?” Rainbow asked out loud, eyebrow raised.

“I’m not sure but that stallion gives me a bad feeling,” Comet replied.


The next day Rainbow had finished the complicated wiring the armor would require. They had used sensors from a guided rocket that helped missiles avoid hitting walls on the inside of the legs. When Rainbow lifted her arms or legs the sensors would activate the hydraulics and lift the suits legs. It would be slow and clunky, but they were working off a box of scraps in a cave. They could only do so much and still fly under the radar.

That task finished Rainbow moved on to the next step. The actual hydraulics. She started looking through their supplies for pistons and cylinders she would need. She found an unopened crate labeled pistons. “Dammit,” she grumbled as she inspected the rusted nails keeping the top of the crate in place. She glanced at the box of tools and spotted a crowbar among the many wrenches and hammers. She grabbed it and attempted to jam it into the space between the crate and the lid, only to miss and smash her hand between the container and the crowbar. Rainbow jumped back letting out a shout of pain. Shaking her hand, she sat down in defeat, contemplating how to get the crate open.

“Need a hand?” Comet asked, seemingly smiling at his daughter’s predicament. Rainbow opened her mouth to decline his offer, some half baked plan to explain why she didn’t need help, but her father simply put a hand on her mouth. “Instead of wasting time why don’t we just get the crate open,” Comet suggested, removing his hoof from Rainbow’s muzzle.

“Yeah okay, magic the stupid thing open,” Rainbow replied, rolling her eyes in annoyance.

Comet shook his head. “Why is it so difficult for you to accept help when it’s freely offered?” he asked.

“Cause it’s never really free,” Rainbow replied, crossing her arms. “Everypony either wants something in return or benefits just as much as you do,” she replied cynically.

“That’s a little harsh,” Comet replied. “No one ever helped you without asking for something in return?”

Rainbow’s mind immediately thought of Spitfire.


“So how goes the new job?” Spitfire asked as she sat down in Rainbow’s living room. During Rainbow’s year long recovery, Spitfire had managed to become a close friend of hers, and now frequently checked up on her.

“No job yet. I have to go back to school and get a few degrees apparently before I even qualify, but if I can build something that can get me back in the air then it’ll be worth it,” Rainbow replied, shifting to get a little more comfortable. “I also have to get an assistant to keep my schedule straight because my dad doesn’t trust me to show up to class on time by myself.”

“So you’re really giving this a shot? I mean we could always look into experimental surgeries or something. I’m sure the Griffins have something. Flight is a pretty huge part of their society. Being a cripple there is like being a criminal here,” Spitfire replied, eyebrow raised.

“We’ve looked into just about everything and this is the only shot I’ve got that’s gonna get me back in the air,” Rainbow said, her brow furrowing slightly.

Spitfire sighed, “Look Rainbow, I’m sorry for what happened...” she said, leaning forward slightly. “I kinda think this is my fault and all.”

Rainbow shook her head. “Nah, it’s not your fault Spitfire. Relax. I just hope Dad doesn’t lose all the funding he has before I even get a chance to work on anything...” she said, annoyed.

“Why would he lose his funding?” Spitfire asked, her voice curious.

“Oh, his military liason quit on him a few weeks ago so now he doesn’t have anyone to talk up his products to the military big wigs and without their contracts Dash Industries will go under in a matter of months,” Rainbow said, rubbing her forehead. “All this business stuff is frustrating.”

“I could take the job,” Spitfire offered, her face obviously showing that she was quite happy with a way to potentially help Rainbow.

“Thanks for the offer, but you kinda have to be in the military to take the job,” Rainbow replied, a wry smile on her face.

“I am in the military. Captain Spitfire of the 205th Airborne,” Spitfire replied, smiling as well. “I joined as soon as I turned eighteen.”

Rainbow gave her a bewildered look. “Oh,” she said, blinking a few times. “You never mentioned that before.”

“Well I’m sort of a poster pony more than anything. The Wonderbolt’s shows raise money for the military,” Spitfire replied, leaning back in the couch slightly.

“In that case as long as my dad’s cool with it, looks like the job is yours,” Rainbow replied as she made her way to the phone in the corner of the room. “Not like he has much choice in the matter anyways. Thanks for the help, I could really use a little less stress,” she said, giving Spitfire a quick glance.

“Don’t mention it,” Spitfire replied smiling.


“Okay well usually ponies want something in return,” Rainbow replied, after a long pause as her father used his magic to jam the crowbar under the crate’s lid, wrenching it off in one go.

“No, you just haven’t met the right ponies yet,” Comet countered. “Or maybe you just haven’t been paying any attention to them.”

Rainbow had no response for that. She started thinking about how she’d treated Spitfire and Caramel over the years she’d known them. She had never really shown them that she actually appreciated them. Sure she’d said thanks before, but she’d always made their work difficult and usually for trivial reasons.

“I’m not a very good friend am I?” she asked, looking down at the ground.

Comet paused, averting his gaze. “I wouldn’t know,” he finally said. “I never tried to be friends with you,” Rainbows eyes went wide at these words. “But the more time I spend with you the more I regret that.” he added, his voice low.

Rainbow smiled as tears began to form in her eyes. She wiped them away before she spoke. “Why don’t we just skip the argument and say we share the blame fifty fifty?” she suggested.

Comet smiled. “Spoken like a true friend,” he answered. “Now let’s get back to work. I wanna treat you to dinner once we get outta here.”

“Sounds good to me,” Rainbow replied.


Rainbow and Comet had been working on the armor for five days and it was nearly complete. They had made sure to keep all the pieces vague in shape and had made dummy designs of some mobile guided rocket system to keep their captors from getting suspicious.

The leader, or ‘Ghost’ as the pair had taken to calling him, had frequently checked in on them, although if he in fact knew what they were actually planning he never admitted it.

Rainbow was currently working on a control panel that would activate the thrusters her father had finished a few days earlier. The Dash’s had become quite the team in the days since they had truly become friends. They weren’t quite at the stage of being a true family, but Rainbow was hopeful for the future.

Rainbow looked over to where her father seemed to be making more fuel tanks. She raised an eyebrow wondering why they would need anymore than what they had.

“What are you making?” she asked as he connected the fuel tank he’d made to an iron tube.

“A flamethrower,” he said without looking up. “Figured we could put a pair on the arms,” he explained.

“That’ll just weigh me down. The armor will be enough to get me through the guards,” she said, mildly annoyed.

“And what about me?” he asked, setting his project down. “We don’t have the materials to build more than one suit and I certainly don’t want to fight those terrorists bare handed. You’ll need to be able to clear a path for me. This is the best way,” he said, his voice somewhat curt.

Rainbow wanted to argue with him, but deep down, she knew he was right. “Sorry, it just always bugged me when you took my inventions and weaponized them,” she said as she grabbed a wire cutter, making sure the wires were the right length, so as to not leave slack, but still be long enough to reach the parts of the armor they needed to reach.

“That’s why the military bought them though,” he replied, turning to look at Rainbow

“Which is why we’re here,” Rainbow was quick to point out, turning away from her work as well.

Comet looked down, almost as if he were ashamed. “I wish we could have avoided making death, part of our legacy, but military funding was the only way we could fund projects to help ponies,” he said, approaching Rainbow.

“Oh please, you can’t seriously expect me to believe you care about helping the world,” she spat at him angrily.

Comet’s face tensed up slightly. “I thought we were passed this. You know I fund projects which could solve world hunger or even deforestation,” he replied, insulted.

“Yeah you have all the time in the world for that but you couldn’t even show up to one of my flying competitions when I was younger. It’s like you didn’t even care,” she said. She knew it was petty, but she felt like making him feel the way she always felt.

“Oh of course I don’t care. I didn’t care when I gave you a job after your dreams fell through. I didn’t care when you wanted to make planes and didn’t have the money. I didn’t care when the board disapproved of how you spent company money,” he said, growing louder with each example.

“You did all that to try to groom me to take over the company one day. You never cared about what I wanted. In fact, I seem to remember you calling my dream to be a Wonderbolt childish,” Rainbow shot back.

“It was. That wasn’t a practical use of your time. Especially given all the money I poured into giving you the education most unicorns would kill for,” Comet retorted.

“Exactly. Most unicorns. You seem to have forgotten I don’t have a horn,” Rainbow replied, waving a hoof over the empty space on her forehead. “That’s what you’re really ashamed of isn’t it? Your daughter has wings instead of magic.”

“Had wings,” Comet said, the look on his face making it evident that he instantly regretted his words. Rainbow’s eyes widened in shock. “Rainbow I’m sorry I didn’t-” he tried to recover but Rainbow ignored it.

“Let’s just get back to work,” she said sharply, turning away from her father and continued working, hoping the stallion didn’t notice the tears that had begun to form in her eyes.

Comet meanwhile, didn’t know what to say. He knew he had crossed a line, but apologizing wouldn’t be enough. Why is it so hard to talk to her? he asked himself, sitting down and silently turning back to his work.


Rainbow didn’t speak to her father the rest of the day. They ate in silence and she even went to bed early to try and avoid him.

Comet meanwhile, tossed and turned in his cot unable to fall asleep. He got up to stretch his legs a bit and started digging through the boxes of supplies, trying to work on something to keep his mind off of the fight. He still felt horrible about what he said. “And just when things were going well,” he said to himself.

His hand bumped against a smooth rectangular object in the box he was digging in. He reached in with his magic and pulled out a small camcorder. It was probably intended for recording tests of whatever Ghost thought his captives were working on.

Comet glanced at Rainbow sleeping on the other side of the cave. He sighed as he set the camcorder on the table and used his magic to turn it on and start a recording. “Hello Rainbow. I’m not sure if you’ll ever see this, but I need to say it, even if you don’t hear it,” Comet began, pausing as he thought of what to say. “I’m sorry I wasn’t a good father.”