A blue, pink, and green barrier wrapped around Shining, Cadance, and Buzz. Changeling magic, based on love itself, slotted seamlessly in with Cadance's power, and hers always married perfectly with Shining's. But despite the effort of the three, the shadow magic picked and bit at their barrier, peeling magic from it like an onion.
"Princess Amore! I destroyed you, how can you be here?" Sombra was in a blind rage, he was hurling power at the shield, ripping away at it. In his mind the torment he had relived over and over in his thousand-year-exile sprang fresh. Amore ignoring him, Amore triggering the Crystal Heart, Amore smashed to pieces. "I don't know how you came back, but I will end you now!"
Shining Armor felt a chill spread from the magic force-field around him, down through his magic and into his horn. As his magic wavered and failed, Shining could feel sharp pains in his horn, of something growing from it.
Seeing her husband slump on Buzz's back, Cadance put her all into the shield. She spared a moment to look down at the fight below, seeing the changelings pushing back the helmeted ponies, the latter seeming severely uncoordinated suddenly. She knew that would change when King Sombra began using his magic on them, again. "I won't… I won't fail…"
Buzz was struggling to hold their magic up to support Princess Cadance, while holding up Shining Armor too. Black magic started to sink into the remaining magic of their shield, and while Buzz couldn't feel it encroach on their own horn, they could see it funnel down into the Princess', growing little black crystals from her horn. Buzzing their wings furiously, Buzz dove under Princess Cadance, catching her on their back.
There was only one left, Sombra couldn't reach the strange pony's horn, but he didn't need to. Wrapping his shadows all around the green shield, he started to squeeze.
~~~~~+++++~~~~~
The train trip was both horribly mundane, and exciting. Twilight was sitting next to Princess Luna, and had to keep reminding herself that she was a princess as well. "Princess Luna, you were introduced as 'Protector of Equestria,' "Twilight felt there was information here that she would find useful, "what does that mean, exactly? I never heard Princess Celestia called that…"
"It is an old title, before the millennium I spent locked in the moon, before I was even sent there…" Luna's thoughts tracked back to that time, when it was her and her sister; Celestia sitting proud on the throne, as they had agreed, and Luna being the steel that every ruler needed. "Tia… Celestia, she was always the better leader. Just looking at her inspired ponies to be good, to make all the right choices. But though she was the soft velvet covering, I was the striking shoe underneath."
Twilight began putting some facts together in her head. "Queen Chrysalis defeated Celestia—"
"Our Queen was backed up by the power of both Shining Armor and Princess Cadance's love, but you are right. Chrysalis could have overwhelmed Celestia even without that, allowing her to remain at full power afterward." Luna remembered watching that, feeling the terror that her sister would be once more under the hoof of a changeling. She smiled a little, I was right, in a way.
"But you were stronger than Chrysalis." Twilight was fighting for the numbers she wanted, that she craved, but all she had was the facts. "So you are more powerful than Princess Celestia?" The question frightened Twilight, the implication that she had gone against so much power when she faced Nightmare Moon almost raised a cold sweat.
"Yes." Luna didn't say the word loud, but she made sure Twilight would hear it. "In the past, Tia would aim me, like a modern doctor does their knife—"
"Scalpel." Twilight blushed hotly the moment she interrupted, but she just couldn't stop herself.
"A scalpel. She used me only when things were dire. Discord, Sombra, Windigo." Luna took a deep breath, her mind playing back each of the fights she named, and countless others. "But every time she had me fight, she would order me back at the end, demand I let the enemy live. We banished, we imprisoned, we did everything we could to make our problems, your problems."
"Our problems?" Twilight tried to follow the logic. Slowly it came to her. "Oh…"
"You carry the Elements of Harmony now." Luna lifted a wing to lightly brush the tiara Twilight was wearing. "You have a lot of power, a lot of responsibility. But know one thing, Twilight Sparkle; Queen Chrysalis has told me to make sure King Sombra is not a problem again, I promised you your chance at him, and I will stand by that, but you must not stand in my way."
"I have a hypothesis about that." Twilight lit her horn and trembled a little. With the Element on, all my magic feels so much stronger. She focused her thoughts down and lifted a small book from her saddlebags. "Discord is locked away again, right?" She waited for Luna to nod. "And he will probably break loose, in another thousand years." Another nod. "But you aren't going to turn around and step right back into evil, are you?"
Luna froze a moment, the tickling in the back of her head, of her Redemption, doing its job of reminding her of how dark she could be. "Every minute of every day, Twilight Sparkle, I remind myself how bad that was. I love Equestria, and I have found out that it loves me too."
It wasn't the answer Twilight wanted, not by a long shot. "My hypothesis might need some work, then." She took a deep breath. "We should be nearing the train station near the returned empire. The castle might even be—"
"We need to go, now!" Luna wasn't looking out the left window of the train, at the spire of the Crystal Castle in the distance; she was looking to the right, the huge dark magic lancing across the sky in the distance. She was on her hooves and rushing to the exit of the train.
Twilight shrugged to her friends and followed Luna. Turning her head to look at what had gotten Luna's attention, her jaw hit the ground. Power boiled in the air, black clouds of magic that made her skin crawl. "We need to get there now…"
"Of course, but only Fluttershy and Rainbow Dash can move—" Rarity got no further. All six of the friends from Ponyville, Spike, and the big changeling Gentle Midnight, suddenly blinked out of the train in a loud POMF.
Luna turned to see the teleportation spell go off. She cursed herself for not wanting to burn up her own magic too soon. "I guess this will give her a chance to make friends with Sombra." Jumping from the speeding train, Luna spread her dark wings and soared into the sky.
~~~~~+++++~~~~~
Buzz barely held, their wings working for all they were worth to stay aloft with two heavy ponies on their back, but the real struggle was magical. It helped that Buzz had Shining and Cadance cuddled together on their back, but the power they were pushing into the shield wouldn't last.
Shining was fighting to keep conscious, trying desperately to keep on Buzz's back and clutch to Cadance. He titled his head to see the magic pouring at them from King Sombra, only to have the sight blocked by a big magenta shield. "W-W-What?"
Twilight's horn was burning with the power she poured out. The Elements, so close and worn by their bearers, spent their own magic into her. She stared up at the King, and lifted her voice. "Sombra! Come down here and talk!"
The new voice, combined with the renewed shield, distracted Sombra from his intended target. He blinked and looked around, spotting the small group of ponies on the ground. They weren't within the line of changelings, still fighting his own army, they were off on their own. "Fit them with helmets!" His fangs tickled the insides of his lips as he roared the command, not that it was needed. He held all his army's minds in his own clutches, thanks to his amulet.
"Ah don't think he wants ta talk." Applejack spun around to deliver two quick bucks to a pair of crystal ponies, helmeted of course. She pointed at the dark unicorn, standing proud on a jutting upthrust of crystals he had summoned.
"I can get up there." Rainbow Dash bunched her hindquarters up, coiling her muscles like springs. Kicking away, she pumped her wings, building altitude and speed both.
Rarity, charged with magic from the Elements, gasped as a pony tried to insinuate themselves on her person. "Oh no you don't. I will not be drawn into roughhousing with you!" She struck backwards with her hooves, as Applejack did; unlike Applejack, Rarity pushed magic into her hooves—achieving the same effect as her friend did.
Rainbow Dash didn't fly right at Sombra, she knew he wasn't stupid enough to let her get away with that. She zoomed around in a spiral of rainbows, winding up into the sky. Every loop she made, she watched the King lift his head to spot her, which was just what she planned. Circling behind him one last time, Rainbow stroked her wings back hard and aimed down. "C'mon, Element of Loyalty…" Rainbow smiled as she felt power pouring off the amulet, wrapping around her wings and body. "Yeah, let's do it for them."
Sombra had a moment to realize that when he looked up, the rainbow-maned pony was not circling. He quickly scanned the sky and saw her, wrapped in more magic than he could counter, aiming right at his platform. "No…" He jumped down, dropping to the ground with a thud.
With Sombra's magic no longer battering their two precious leaders, Buzz turned and dropped back down into the army of changelings below. Looking around in panic, Buzz couldn't find anypony, or anyling, who could spare time to help.
"King Sombra!" Twilight strode forward, her friends wading through the disrupted army of helmeted ponies. "Stop this, please." She ended up no less than ten yards from him. "You don't have to fight, to hurt."
"You are wrong." Sombra summoned his magic and dodged to the side as Rainbow Dash roared through the air he was standing a moment before.
"Rainbow! Get down here!" Twilight turned to catch her friend in a bubble of magic. Turning back, she found Sombra was only five yards away now. "I am sorry, we need to talk this through. Why are you like—"
"Like this?" Sombra's mouth pulled up into a smile that showed off his fangs. "It is simple, she made me this way." He pointed his hoof toward the army. "Princess Amore! Can you hear me? I am going to petrify you again, Amore. I am going to—"
"Who are you talking about?" Twilight stomped a hoof, not liking being ignored when she was doing her best to save Sombra.
"Princess Amore. The former leader of the Crystal Empire. I petrified her, shattered her." Sombra sneered at the gasps from the six ponies. "And I don't know how you did it, but it will be my pleasure to do it again."
"Princess? The only princess here was Cadance." Twilight stepped forward this time, standing right in front of Sombra. "No pony here is from your time!" Twilight saw the slightest bit of recognition in his eyes. "Sombra, please let's just talk."
"Talk? Talk?!" Sombra turned his full attention on the little mare, and saw something that terrified him. "The… Elements…" He started to step back. "No… no!" Black smoke wrapped around him, he pulled his power back from his army and started to withdraw.
"Listen to her, Mad King." Luna crashed to the ground behind Sombra, sending a wave of earth radiating out from around him. "She is the only pony here who will fight for you."
The Elements of Harmony, and now Princess Luna. Sombra decided in an instant that discretion was the better part of pretty much everything that didn't result in him losing his head before sunset. Pouring power into his body, he faded into the smoke around him and fled.
"No!" Luna crashed her power down around her, trying in vain to force Sombra to reform. "Come back here you coward!" She spread her wings and was almost into the air before a shimmering wall of power appeared before her.
"Stop, Luna wait." Twilight leaped up beside Luna. "Don't go alone, he might have a trap of some kind. Besides, you are the only pony familiar with his magic." She gestured to the field around them, at all the helmeted ponies who had suddenly stopped dead in their tracks. "Like what is going on here?"
Trampled into the ground, its shine hidden, an amulet glinted once more with the big red stone mounted in the center of an alicorn's chest, before the mud claimed it.