Shining stood at the altar as Celestia went through her very long wedding speech. As he had expected, the fake Cadence continued to get more and more antsy and impatient, even going so far as to grind her teeth. Shining, meanwhile, did his best to maintain an expression of abject, mindless obedience, waiting for the opportune moment. As the speech wound down, he wondered what was taking Twilight so long.
Then again, maybe it has to wait for a dramatic moment or something, Shining thought to himself.
"If there are any here who have sound reason why these two should not be wed," Celestia spoke up, "speak now, or forever hold your peace-"
The doors at the end of the hall burst open in violet light.
Dramatic moment it is, Shining thought to himself as everyone - him included - turned towards the door. What he saw there nearly made him lose his focus on maintaining his 'mindwiped' look.
She was a bit dirty, a bit bedraggled, and more than a little out of breath, but just the sight of her - of his Cadence - sent his heart leaping into his throat as his blood raced. The entire world took on a brief white sheen as he stared into her eyes, only just barely keeping himself from breaking cover by running to her side.
"I have an objection!" Cadence proclaimed angrily as she stepped into the hall, Twilight right behind her as she closed the doors with her magic. "That's not me! She's a Changeling! They take the place of ponies you love and feed on your love for them!"
Changeling, huh? Shining thought to himself. So, shapeshifter? ...wow, I really am in love. I don't even find that concept kinky anymore.
As he watched, the false Cadence became surrounded by green fire, her body changing. Her coat turned to black chitin, holes appeared in her lengthened limbs, her mane turned green and stringy, her wings became holed moth wings, and her horn became twisted. Last of all, her eyes turned a bright, glowing green.
She laughed as she revealed herself. "Good guess, Princess," she purred, her voice echoing curiously. "I am Chrysalis, Queen of the Changelings. And as their Queen, it is my job to find food for my subjects. Equestria has more love than any place I ever encountered."
As Chrysalis spoke, she slowly walked towards Cadence. Shining silently followed along behind, acting as though he were under control...though he noticed Flash Sentry slowly moving through the crowd, the Eco Blades strapped to his back, always staying within easy telekinetic reach.
"My fellow Changelings will be able to devour so much of it, that we will gain more power than we have ever dreamed of!" Chrysalis gloated eagerly.
"They'll never get the chance!" Cadence proclaimed angrily. "Shining Armor's protection spell will keep them from ever even reaching us!"
That's my cue, Shining thought to himself as he moved into position behind Chrysalis.
Chrysalis chuckled wickedly. "I doubt-"
"You got that right, Cadey!"
Before Chrysalis could react, Shining spun around and kicked Chrysalis right in her plot with both hind hooves, focusing his magic internally into Red Eco for an extra kick. Chrysalis went flying to slam into the closed doors with a satisfying thump. She scrambled to her hooves, wincing and blinking. "What? How? You were completely-"
"Faking being under your spell ever since just after my bachelor party," Shining interrupted. "I admit, I've let the shield weaken a bit..." Drawing on magic and his own life energy to generate Green Eco, he shot an amplified spell up into the dome. If flickered pink and green, blazing with light. "That ought to hold off your army until my backup arrives. As for you..." Reaching over with his mind, he pulled his Eco Blades from their sheath on Flash Sentry's back, levitating them to his sides as he activated their Yellow Eco charges, figuring sword beams would be more useful than air-splitting slashes just now. As he did so, he ripped his dress uniform off, revealing the Precursor alloy armor underneath as he got combat ready. "You have the choice of under arrest, or six feet under."
Chrysalis was staring in disbelief. Twilight was wide eyed in confused excitement. ...Cadence was licking her lips eagerly. "Woof," she purred seductively, shivering in delight.
"Not now, Cadey," Shining chided playfully. "I have a dangerous criminal to apprehend-"
At that moment, a guardspony slammed the doors open, coincidentally smashing Chrysalis between the door and the wall. "Your Highness! Captain!" the guard called out worriedly. "There's a swarm of Changelings attacking the shield dome...and on top of that, the Everfree Forest is...invading!"
Celestia blinked twice. "I...beg your pardon?"
Curiously, Shining moved to the window and looked out. In the distance he saw a massive bipedal forest beast walking towards the mountain, as though an entire forest simply stood up and started to march. He could see green plants, glowing energy, and black thorny vines all intermingled with rainbow-colored light...and the silhouette the forest created was very familiar. I'll have to ask him how he pulled that off, Shining thought to himself. "No worries, soldier," he told the guard. "That's my backup."
From the look on Celestia's face, Shining greatly regretted the fact she wasn't drinking anything. The spittake would have been priceless. "Captain, when this is finished, you have a lot of explaining to do." She gazed out the window as thorny vines lashed out, seizing the Changelings attacking the dome shield and dragging them into the thorny interior of the forest creature.
"I'm sure-" Shining began.
Chrysalis lunged out from behind the door, threw her forelegs around Cadence and Twilight's throats, and shifted those legs into blades. "You're going to call your backup off," she stated bluntly, "and my swarm and I will be leaving...taking these two with us. One false move, and I'll be happy leaving one - or both - behind as corpses!"
Gasps echoed around the hall...and as Shining's vision of the world turned red-tinged green, those gasps became screams. Red light seized the blades Chrysalis' forelegs had become, bending them back against her limbs. Her screams of pain as she was forced off Cadence and Twilight were music to the Black Knight's ears.
He vaguely heard Celestia gasp something that sounded like 'Sombra?', and just as vaguely saw Twilight back away in fear. At the moment, all his focus was on Chrysalis...the one who tried to take away those he held dear. He watched her fear, watched her pain, drank it all in. She would suffer...
Before he struck, he felt something warm pressed against his side. "Shining...this isn't you," Cadence whispered in his ear. "I don't know what's happened to you...but I know you, your heart. You're stronger than this. The stallion I love is strong enough...to not give in to hate. He has too much love in him..."
The Black Knight struggled, trying to push back against the warm feelings...but Shining welcomed them in, embraced them, and as he nuzzled his bride-to-be, he felt the Light within awaken.
All were briefly blinded by the blaze of Light that encompassed everything within the shield. When it faded, any Changeling who had been seeking to do harm to the citizens of Canterlot found themselves locked in their natural forms, all their natural magic - even flight - completely blocked. As the light withdrew to the hall, gasps once more filled the chamber.
The White Knight stood tall, taller than Cadence, almost as tall as Celestia. His body was more stretched out than before, built more like an acrobat than a soldier. Mane and tail flowed in a nonexistent wind like pieces of a blue river, and his eyes glowed solid blue-white. But what drew all attention was his spiraling horn...and the two wings of pure Light energy spread to either side of his body, one gently draping around Cadence and rejuvenating her.
Chrysalis stared at The White Knight, and at the blades pointed at her that glowed with Darkness and Light, and did the only sensible thing she could think of. She raised her hooves over her head. "I surrender."
The White Knight's eyes flared, and Chrysalis vanished, warped to the dungeons. He then relaxed, shifting back into Shining, most of the excess Light Eco shooting up into the dome to give it extra strength. "Thank goodness that's over with," he murmured softly, pulling Cadence closer with his wing.
Slowly and carefully, he turned to confirm what he'd just done visually. Yes, the energy wings of his Light Eco form apparently had remained when he reverted, turning to flesh and feather. Okay...didn't expect that. He noticed that everyone in the hall was bowing. ...probably should have expected that-
While he might not have known what was going on, it apparently made Cadence very happy, as she lunged for him and pressed her lips to his own. He quickly stopped caring what was going on.
"Ahem," Celestia spoke softly, catching their attention. "Perhaps you can save it for after the wedding?" She chuckled at Cadence's petulant expression. "Wedding and coronation, I should say. Cadence, perhaps you should see about arranging the wedding more properly? For now, the Captain-" She stopped herself, turning to Shining with a raised eyebrow. "The Prince still owes me an explanation."
Shining shrugged to himself as shocked murmurs raced through the crowd. "Very well. But be warned, it's a doozy."
"I'll go get the pointy-eared humans!" Twilight's pink friend - Pinkie Pie, he believed - called out, dashing towards the outside of the castle.
Shining blinked a few times, then decided not to question it. Jak and the others did need a guide, after all. Instead, he gave Cadence one last kiss, then followed Celestia to a private room. "Now...you wanted an explanation?" he began.
"Yes," Celestia murmured softly. "If I owe Luna 10,000 bits on that wager of ours, I certainly want to know why."
"Wager?" Shining asked in confusion.
"Later," Celestia demurred, focusing on Shining once more. "Let's begin with a simple question.
"How have you come to access Eco?"