Wind Chaser led the flight of changelings south through the streets. Downhill, toward the south gate, and the mists that were even now starting to spill over them. She felt the oppressive weight of the sword bearing down on her back, along with the even more oppressive weight of responsibility. Not only for herself, her fellow changelings, and the innocent ponies behind her; no those were all relatively easy to safeguard. She had new eggs growing within her, that she hadn't had a chance to lay yet. Those... those were dangerously vulnerable, even with all the nanotechnology in the world.
Fear began to gnaw at her, only to suddenly vanish, as the blade of the sin eater touched her back and became wreathed in a faint black layer of writhing energy. She grinned, her resolve renewed, as she picked up the pace, drawing the rest of the changelings along with her. The distance melted away, bringing them as close as they dared to the oncoming mists.
She brought the patterns to mind for a simple wind spell. While it took some work, and sometimes a bit of trial and error, to translate spells meant for a unicorn's horn to a changeling's native equivalent, they had already taken the time with Midnight Oil to do so for a small variety of the spells she had researched, starting with some of the basics of weather control. If they'd known back then that they'd end up fighting vicious clouds, perhaps the unicorn filly wouldn't have been so disappointed with her alma mater.
Driven by the changelings' horns, powerful winds swept through the approaching mists, shredding them layer by layer, but more were still pouring over the wall, climbing it in defiance of gravity. For a moment, a sense of futility began to seep into their hearts, creating a new fear. From here, the mists cascading down the walls looked like a waterfall rendered in stark monochrome, black rippling down over the gray stone bulwarks. Again, the sin eater pulled Wind Chaser's fear away. Taking the handle in hand, she let the black energy flow into her, and then redirected it, sending it on to her king. That restored her resolve, but already she could see her siblings beginning to falter. [Don't be overwhelmed. It's just a misbehaving cloud,] she chided them across their link, before tapping the sword's blade against each in turn, ripping their fear away and sending it on.
It was easy to say, but their love was being depleted with every gust of wind, every beat of their wings, and the mists showed no signs of letting up. Focused on the fight before them, the ponies that normally fed them were far too concentrated on other things to generate more for them. But even if they weren't being fed that moment, they had fed deeply before the battle, and their reserves were far from depleted.
Wind Chaser broke off from the others, pushing herself upward to clear the top of the wall, getting up above the mists. Digging deep into those reserves, she charged her horn and swept the top clear with a powerful gust, revealing the tops of the stone. Another and another, powerful winds ripped through, keeping the top clear, and before she was forced to land atop one of the guard towers, her fellow changelings had eliminated the mist from within the city limits and now rose to join her with a shout of triumph.
"We've driven it back to the walls!" Mirage stated the obvious as she alighted beside Wind Chaser.
"A good start, but we haven't even seen the real enemy," Wind Chaser countered grimly. "That ends now!" Calling up all the love she could muster, she sent a torrent of air flowing down into the inky depths before her, stirring the mists into a roiling chaos. Here, where the air was nothing but mists, the wind could do little to eliminate it, but the churning left momentary gaps as it ebbed and flowed, and she was quick to spot large solid shapes moving within the mist.
"Keep the mists from climbing," she ordered, as she moved to the edge, one hoof already on the guardrail before Mirage stopped her with a hoof on her swordhoof.
"You're spent, and you're needed here to command," Mirage pointed out, before putting out a hoof expectantly. "Allow me."
Wind Chaser let out a sigh with the relief she hadn't expected to feel as she passed the black-runed blade to the other changeling. Mirage was very well fed, perhaps the best in the kingdom now that Wind Chaser had expended so much of her own energy. Mirage's mate had managed to earn a cutie mark in feeding changelings love, or so she described it, and all of that love came into the kingdom through her. Not only was her carapace nicely hole-free, but with the gorging before the battle she actually was looking a bit pudgy. That wouldn't last long.
Now that she had the blade, though, Mirage had to take a moment to steel her own heart, hoof resting on the guard rail as she looked down at the enemy. "For Stud Muffin!" she shouted, before leaping off. Buzzing, incandescent wings guided her descent, increasing her speed until it was time to pull up, skimming just above the mist. The sin eater lashed out, its blade hungrily devouring the mist's energies, as Mirage funneled it up to the Itinerant King as fast as she could. Let it be his problem. She had enough of her own.
A massive claw lashed out at her from the mist. It would have landed a blow unseen, had it not been for Wind Chaser sending her the view from her own eyes. As it was, Mirage was barely able to turn, blocking the blow with her blade and being forced back, downward into the mist. The changeling shivered with fright as the mist wracked her will before the enchanted blade could finish absorbing it from around her, leaving a small clearing of snow revealed. But her attacker was still hidden from her.
A powerful gust of wind, directed downward at her location, solved that problem momentarily. It drove the mist back, causing it to pile up around her like a wave cresting, preparing to fall back down upon her, but it revealed her nearest adversary. It was a crab nearly eight feet tall, towering over the insect-pony with its massive black carapace, deadly onyx claws and alien looking crustacean face, oozing out a thicker, almost liquid version of the black mist, which dissipated into the air as it descended. But one detail of its features gave Mirage hope. Its front right leg was shorter than the others, cut off at the lowest joint, a victim already of the sin eater's power.
Tapping the blade with a hoof to let it eat her own fear, Mirage lunged forward, pressing the attack with desperate aggression. The closest thing to a defense she could afford was to block lashing limbs with her blade, as the mists began to flow back down to fill the gap. Fortunately, sturdy as the crustaceans shell appeared, it evaporated at a mere touch of the blade, and soon Mirage alighted upon the things back, driving her blade home and vanquishing the creature entirely. Nothing was left in its wake but the sword-wielding changeling.
Mirage laughed loudly, almost manically, as her foe fell before her. She saw another one, a bit distant, hidden in the mists, but she could just make it out, so she charged, buzzing swiftly through the air as she brought her blade to bear against the next. She slid under it, slashing through its underbelly in a deadly flyby attack, leaving it to dissolve into mist behind her.
They were getting easier to spot now, so she flew for the next, but this time she didn't want to make it quite so easy. She aimed for the legs this time, cutting them off one by one with quick, darting approaches, until the enemy collapsed to the ground, unable to hold itself up. Only then did she finish it off with a vicious chuckle.
She was running low on things to cut. Just one last crab, and she took her time with it, slash after slash, nicking it bit by bit when it was no longer an immanent threat, seeing just how many blows she could drag the fight out with before it finally expired. She was disappointed for a moment when the mists finally dissipated, until she saw a figure remain within, cowering in fear and pain. A pony! This must be an evil pony warlock of some kind, surely!
Blood marred the blade from one wound, then another, then another, until a blast of raw, green magic slammed into her. A changeling, wreathed in black mists, approached her angrily, wings buzzing with agitation, horn glowing with power. More followed behind her, ready to back her up. A trick of the shadows, no doubt. Who knew they could make fake changelings with their power? No matter. The blade would solve this problem as well.
The changeling proved frustratingly agile, dodging blows and even deflecting them with bare hooves, as the swordfight quickly became an outright grapple. But finally Mirage managed to get the upper hoof, knocking the other changeling to the ground, and pulling her sword up to bring down a death blow.
"Stop!" the changeling ordered, and to Mirage's chagrin, her body obeyed. "Give me the sword!" Again, her muscles acted unbidden and released their grip on the handle. Forced to stillness, Mirage suddenly realized the other changeling's lips weren't moving, and then remembered they had been moving earlier, when she hadn't heard a thing.
When the blade was brought to her own carapace, the black mists rolled away from Mirage's vision, no longer surrounding the changelings she saw before her. She recognized Wind Chaser standing before her. She looked down in horror as she saw the blood-stained crystal pony who had passed out from his wounds, realizing how close she had come to taking an innocent life. Her kingsblood helpfully matched his features to her memories, identifying one of the guardsponies who had been present when they arrived in town, but missing since the mists first approached. She collapsed to her knees, tears slowly breaking past her resistance and flowing down her cheeks.
Wind Chaser spared a moment to hug her, before standing back up. "Take him to the fortress, downstairs. The rest of you, come with me. This front is handled, but we're still under siege."
They moved with haste, but conserved their love, hoofing it rather than taking flight. At a silent order, the gate was opened, admitting the victorious forces.