Things were finally settling down again in Canterlot's court, well over a week after the attack and subsequent spectacular defeat of Chrysalis' hordes.
Among those particularly relieved by the change were the royal guards, who were no longer expected to be ready to help the clean-up at all hours of the day or night. While the guards trained hard, they were used to at least something of a schedule.
But it was the nature of the cleanup itself that still rested heavily on the mind of one Mirrored Shield, pegasus guard sergeant.
Cleaning up after a hostile attack by changelings… He knew it was something that had to be done, but it made him… ill. As much from remembered guilt as anything.
A decision solidified itself. It was surprisingly easy.
The unicorn standing duty with him looked over. "Sir?"
"Mind covering me for a moment? I've got… something to talk to Her Majesty about."
Spear nodded understandingly. Celestia had long had the policy that any, pony or otherwise, could talk to her in private if they were cleared by the guards.
She said she enjoyed being able to talk normally.
The guards themselves occasionally used the privilege to discuss things with her, whether important matters that needed to be handled discreetly - such as the logistics of a surprise royal visit – or simply a personal matter that might require attention.
The guard captain, then a recruit, had made use of it to quietly ask for Celestia's permission to date her niece some years before. The story still made the rounds in the barracks every so often, whenever a new recruit needed reassuring that the captain was a pony, as well.
Remembering being told that was part of what let Shield make his decision.
She was no tyrant. Not Celestia.
Nodding his thanks, Shield rapped twice on the Princess' door.
"Come in – I'm up." Celestia called through the door, and he entered.
"Ah, sergeant." Celestia said, as the pegasus closed the door behind him. "Something important, or just pleasure?"
He swallowed through a suddenly dry throat. This close, he was starting to have serious second thoughts.
Would she take it well? How would she react?
"I'm afraid it's something of some importance, your Majesty." He managed, voice steady enough to surprise him.
"Oh, none of that. I get it all the time. At least use my name, sergeant." Her eyes shone with humour for a moment, the humour of someone so old they had to find jokes in everything.
He could read her like an open book, in that at least. But he still didn't know if what he was doing was sensible – or even safe.
Enough. Like a soldier, not a spy.
He trotted to the centre of the room, and knelt. Celestia began to react with confusion, but he ignored it.
One last breath, made slightly uncertain by fear.
"I swore an oath, princess Celestia." The sergeant said, simply. "To you, and to Equestria."
And he dropped the transformation he'd held for months.
Celestia's first reaction was pure shock. A changeling? How had it infiltrated her guard so quickly – was it one of Chrysalis' contingency plans?
Was this an assassin?
She almost acted on instinct. Almost called down the fire of her sun – almost called the guard – almost, almost, almost.
She didn't know why, but she didn't actually do it.
Curiosity? She had that. But she was a ruler. She couldn't afford to make mistakes for something like curiosity.
Was it confidence? Perhaps. Certainly the only Changeling to pose her a threat – albeit a substantial one – was the Queen, with a month or more of powerful love siphoned from her own guard captain. And she couldn't sense the subtle stress such an accumulation of magic would create. Even the Queen had only been able to disguise her stockpile behind the smokescreen of an alicorn form.
But, again, that wasn't quite right. She knew when she had to make the right choice, irrespective of her own opinions.
That was it. She felt that staying her hoof was the right choice. For whatever reason, the actions of this changeling were atypical – and not threatening.
"Explain." She said, simply.
Shield – or Mirror, as his original name had been – looked up. "As I said, my princess. I swore an oath. While I did not originally mean to fulfil it… I have changed."
He absently tasted Celestia's emotions. By the feel of them, he would continue to live for at least a few seconds longer.
"I will explain further."
"Please do." Celestia sat back on her nearest chair, and gazed steadily at the changeling.
"To begin at the beginning. I was one of the advance scouts. Sent into Equestria years ago. Planning, infiltration." Mirror's eyes looked down, unwilling for the moment to meet the princess' gaze.
"So that the Queen's attack would have good information. I see." Celestia did see. It was good practice. Whether planning a war, of the kind Equestria had not seen in hundreds of years, or just a good surprise for entertainment.
"More. Ambush." The short sentences seemed to make Mirror more comfortable. "Trusted allies become enemies."
After a moment's thought, Celestia concluded that, yes, that was good sense as well. If it was possible.
"So…" she mused, aloud. "Why didn't you?"
"Trusted." Mirror replied. He closed his eyes for a moment, then steadied himself visibly and began to explain in more detail.
"It was easy, to start. Come into Canterlot. Shape of pegasus. Made up pegasus, with similar name. Makes it easier."
"Easier to disguise?" She interrupted, curious.
"No. To remember. Made up pony, nobody to tell mistakes. Similar name, so I could react to it."
"Mirrored Shield…" she repeated the sergeant's – apparently false – name. "So, what is your real name?"
"I see. Interesting. I can see how that relates to changelings." After a moment, she was struck by a new thought. "Before you go on, I'd like some more information on how you 'made up' the pegasus… body?"
"Started off, spying as other ponies. Would see a pony in the street. Disguise as them somewhere else – don't run into the real pony." The last part was said as if an oft-repeated mantra. "Notice how pegasi, unicorns, earth ponies behaved. Decided that pegasus was easiest." He felt her attention shift and answered. "Horn magic – always same green. Giveaway. So not unicorn. But…" here he looked a little happier, remembering a different time. "I wanted to still fly."
Celestia felt a stab of pity. She hadn't considered that angle of it before – a disguised changeling was limited in body, or magic, or perhaps both. While it was hardly an excuse, it was… tragic.
"Invented pegasus. White, white wings, silver mane. Name fits. Easier to remember the disguise. Simple, and different to… me." He gestured to his black body. "Emblem… obvious. Bright silver shield."
"And then you infiltrated the guard." Celestia's tone cooled noticeably.
"Again, easy. Said I was from out of town, wanted to join. Entered easily – fit enough. Body invented hours before to be fit. No point inventing unfit body."
He shuddered, remembering. "Then, oath. Swore to serve you, lying all the time. But then…"
The changeling fell silent. Looking closer, Celestia saw a tear in his eye.
"Training, we were in a squad. The guard train together." His mode of speech changed again, returning to the style of a guardspony. "We… I don't have the words. As a changeling, you get used to draining others of their love or affection for another, but… but… I had never encountered camaraderie."
He looked up, finally making eye contact. "It is sincere emotion. A kind of love. Directed at me, for my deeds, not the pony I imitate. There's something… purer about it. I know that none of the others in my squad ever seemed the least bit drained, for all that I sometimes drank deeply enough that they should have."
Mirror looked down again. "Maybe that happens for all properly placed love. I don't know. None of us do. But I felt it, and it sustained me, and… by the time I finished training and took the oath again, I meant it."
"And I have never stopped meaning it."
Thinking back, she remembered Mirrored Shield's actions during the changeling attack. He'd run interference for his squad, somehow able to catch and knock out any changelings – any other changelings – who tried to imitate the guardsponies or those they were protecting.
"I could not get close enough to help you, your majesty. Chrysalis… she would have seen me for what I am."
Celestia came to a decision of her own.
"She would have seen a royal guardspony, doing his duty to the best of his ability. Nothing more."
Mirror looked up, startled.
"I understand the bravery it took to explain this to me, sergeant. And your loyalty is something that humbles me. If you have any problems with your… unique situation, do inform me. And if I ever have need of your talents, I will send for you. Aside from that…" She smiled, warmly, and a rush of understanding and good will flowed through the room.
"I believe you should continue as you were."
Mirrored Shield stepped back out of the elder royal sister's private room, nodded his thanks to Sharp Spear, and took up his vigil once more.
He felt better than he had in months.
So, yes. Changeling story.
This was written with the intent of analyzing how changelings might go about infiltrating Equestria (as opposed to the kind of short term mimicry that shows up for the most part), along with the topic of one "going native". It's a lot more introspective than I normally do.
For the curious, Mirrored Shield's "talent" is the ability to ignore attacks (where they "reflect" off him, as if off a mirror), which is actually Mirror shapeshifting into an uninjured version of his body as the attack hits.
I might go on to do the "special duties" that he would get, largely places where a trained guard capable of either shapeshifting or sensing emotions would be especially useful. Equestrian Black Ops? (Especially given his colour...)