The zagged arc of black lightning coursing at Spike’s head misses purely to the dragon suddenly dropping six size categories. Instead it dissipates into the cracked ground, leaving scorch marks and the strong scent of ozone. Spike groans, rolling into one of the many depressions he made, trying to find a tiny bit of cover. King Sombra bares his fangs, his horn glowing until he is pelted by every rock and shard of crystal caught in Twilight’s shield.
“Back away from my Friends!” Twilight bellows as her hooves slam into the ground, sending up a cloud of obscuring dust. Except when Spike starts coughing, and Twilight’s enraged expression drops to one of worry as she glances back at her Best Assistant. “Spike? Are you okay?”
“Ugh,” Spike says, claw gripping his side and trying to get the pain to go away. “I could go for a nap right about now.”
“You’ll be able to take all the naps you want after this,” Twilight says with a smile. Hopefully he is okay, but as long as he’s conscious that’s a good thing. Then her ear twitches, her focus returning to the unicorn who has certainly not spent the last few seconds being sentimental.
Underneath the Crystal Castle, everypony gasps as dozens of crystal spears lance from King Sombra. Twilight merely narrows her eyebrows; a raspberry glow surrounds the road, ripping the pavement up and forming a solid wall. Up on the balcony, a very distraught Fluttershy finds a purple dragon suddenly appearing in her hooves. Instincts take over as she hides out of Sombra’s sight, able to assess his injuries in relative peace.
King Sombra bellows in rage as every one of his spears impacts into the wall. His horn glows, a shockwave rippling along the ground that blasts the wall in half. A second explosion kicks up a massive cloud of dust right where Twilight and Spike were hiding. Fragments of rock blow in the chill wind, and King Sombra grins as he takes a few triumphant steps forward. He chuckles as he waits for the dust to clear, the battlefield silent but for the muffled cries of a few ponies.
If those ponies weren’t watching so closely, Twilight might have kept the element of surprise. As it turns out, a few ponies looking up and pointing behind Sombra gets the unicorn to glance backwards. His eyes go wide, his horn immediately lighting and turning himself to smoke.
Twilight roars as she slams down her hollow crystal, completely encapsulating Sombra’s cloud.
“Hah!” Twilight yells with a smirk. Then her makeshift prison bucks, the bottom lifting off the ground an inch. Twilight scowls, her aura forcing the crystal back down to the ground. They go back and forth, the crystal sliding along the uneven ground, every now and then slipping out a inky tendril that gets forced back underneath by a raspberry glow.
Meanwhile, the Crystal Heart that Spike threw zips past the center of the Crystal Castle. Queen Chrysalis holds on for dear life (or at least a strongly developed sense of vengeance), But, like a comet stuck in a doomed spiral, it decelerates, a wide arc that takes it right back towards the glowing circle underneath the castle. All her efforts to manipulate the crystal fail, up to and including trying to teleport herself and the Crystal Heart away.
After a few more revolutions that leave the queen of the changelings reeling the Crystal Heart settles into place. Two blue cones spring, one from the ceiling and one from the floor - conduits to channel the energy of the crystal ponies to the entire Empire.
But then nothing happens. Queen Chrysalis pauses in her struggles, inspecting the Crystal Heart. It certainly isn’t empty, she can feel it pulsing with power. Maybe it needs some sort of trigger to start going? And, if she is there and happens to absorb a bit of that power? She won’t complain.
“TO ME!!” shouts Queen Chrysalis, her buzzing wings and flailing limbs drawing everypony’s attention from the duel. “Send your love to me!”
“Cadance is right!” Rarity demonstrates by kneeling towards the Heart, focusing her deep love of her fellow ponies and the knowledge and hope that things will all work out. Applejack joins her, and Pinkie Pie; even Rainbow Dash lands to concentrate solely on sending all of her love right at the Crystal Heart.
At first nopony moves, many too busy watching Twilight struggle to contain the dark spirit of their former King. Then one, then three, then a dozen; soon, every crystal pony has turned to the Crystal Heart. They bow, their eyes closed, solemn expressions on each face. The ground underneath them lights, turning the bright blue of a clear sky.
Energy arcs in every direction, all twelve roadways gleaming with power. A massive sigil appears: a six pointed star radiating away from the Crystal Castle, as if the entirety of the Crystal Empire was built purely to serve as a conduit for channeling this power.
Twilight ceases her struggling with Sombra to gaze at the glory of the Crystal Heart; Sombra takes the opportunity to peek out from his crystal cage. His eyes shine with fear as hers shine with hope.
Queen Chrysalis basks in the reflected love of everypony as it pours into the artifact next to her. Even trying to take a sip is like drinking out of a fire hose, and she is content to imbibe just the mere droplets that are flung off. She feels more full than she ever has before! Like that hunger: that ever present, insatiable, unyielding thirst for power could somehow be quenched!
She gasps, as if the ability to do so is right there, right on the tips of her hooves. And it is! All she needs to do is join her subjects… her underlings… her… Friends?... in giving, in sharing that love! But, she needs that love! If she gives it away, she won’t have it any more! It will be somepony else’s!
Queen Chrysalis nearly gives in as the Crystal Heart wrenches - no, it doesn’t try to force her love from her. It’s far more insidious than that, appearing as a gentle request, a simple solicitation. It would be so easy to give in, like she has seen so many ponies give in to her illusions and trickery. Promising exactly what she wants to hear?
Hah! She is better than that! There’s no way that she would even think of-
Chrysalis breaks her gaze away from the Crystal Heart, now rapidly spinning, to stare at her hooves. They’ve turned… translucent. And sparkly. She can sort of see through them.
It’s exactly the Nightmare that King Sombra forced on her!
Queen Chrysalis sits for a moment longer, entranced, until a bubble starts to push away from the Crystal Heart. She knows what that bubble will do. It will consume her like she would consume Equestria, chewing her up and spitting out something that, while it might look and sound like her, have lost everything of what it means to be a changeling.
And that is something that she cannot let happen!
Queen Chrysalis bursts away from the Crystal Heart as the bubble expands. Flying faster than she ever has before, burning away every ounce of love she consumed, and it still isn’t enough! The bubble continues growing, inching closer and closer, threatening to eviscerate her soul!
King Sombra seems to have the same idea of what the expanding bubble of pure love will do to himself. He turns, trying to run away, but the crystal cage is in his way. Consumed by fear, he can’t even think to back away several feet in order to retreat correctly - the terror of the love is too powerful, and the most he can do is push against the crystal cage and Twilight Sparkle’s magic in a vain bid to flee.
Twilight Sparkle seems to catch on, holding the cage like a cup and letting the pure love wash over herself and King Sombra’s form. He doesn’t even get a proper death scream, just the clatter of his horn falling to the ground.
The light and love of the Crystal Heart rapidly spreads throughout the Crystal Empire. Any remnants of King Sombra’s corrupting dark crystals disappear without a trace, even the dust scattering and blowing into the no longer chill winds. The cracks and gouges in the roads fill in, and even the buildings rebuild themselves in pristine condition.
Not only pristine, but scintillating: every inch of the Crystal Empire sparkles, and not just the terrain. Everypony, and everydragon, inside has transformed, crystalline versions of themselves that shine like the radiant dawn. They all look at themselves and each other in awe, amazement at the beauty shining from each of them.
Rarity seems to put it best. “There are… no words!”
The bright blue bubble that surrounds the Crystal Empire shines like day, releasing blue and pink and yellow torrents of light into the night sky. They spread, higher and higher, soon visible throughout all of Equestria.
In Canterlot, Princess Celestia and Princess Luna look up from their planning. They trade ebullient grins, leaping up to wrap each other in a tight hug.
“She did it,” Luna says quietly, sorry she ever had any doubt.
Celestia merely smiles, nodding into her Sister’s mane.
“Twilight!” a fully healed Spike calls as he leaps from Fluttershy’s forelegs, wrapping his arms around her neck. “You did it!”
“No, Spike,” Twilight replies, nuzzling Spike happily. “We did it. All of us.”
“Regardless, it was very impressive,” Doug says as he walks up to Twilight, lifting her into a firm embrace. The human doesn’t seem to be that put out that he is the only creature in the entire Empire not sparkling and transparent. “Well done.” And, as he buries his face in her neck and mane, he whispers, “I’m so glad you’re safe.”
“Me, too,” Twilight whispers back, inhaling the sweat of her stallion. She chances a glance at Pinkie Pie, the mare bouncing up and down. Somehow, she seems to have taken a page from Sombra’s book, her party hats periodically exploding into more party hats that find themselves landing on everypony’s head.
The party rages for only a little while before the light shining off the Crystal Empire’s shield starts to fade. The ponies reluctantly say good night to each other, returning to their homes and leaving the Element Bearers standing at the base of the Crystal Castle.
Twilight Sparkle stands among them, smiling at all her Friends. But her tone is grave as she clears her throat. “As much as I know we want to go home and rest, unfortunately, Chrysalis is still out there.” The mood instantly goes from jovial to somber, Rarity and Applejack nuzzling a now downcast Shining Armor. “And, since we need to find out what happened to Cadance, we’re going to have to keep the deception going a little longer.”
And yet, Twilight’s encouraging smile is enough to lift everypony’s spirits; Pinkie Pie would be, and is, quite happy with the result. “I know we can do it. And together, we will!”
Smiles fades as hidden yawns become more and more visible. The ponies gather their things, finding one of the open rooms on the ground floor to spend the night.
Only Twilight Sparkle remains, sitting on the balcony and staring into the heavens. She did it. The faith that Celestia and Luna placed on her was well founded. She can do it! Anything she can set her mind to! She is prepared to pass any test! She smiles, giggling softly to herself, until she hears the faint flutter of wings next to her.
“You best not even think of laughing, Sparkle.”
Twilight Sparkle turns, unable to keep the smile from her face, but it isn’t mean or malicious. Instead, the happy smile just from seeing a friend return. Well, not a friend; the Crystal Heart removed any trace of Chrysalis' manipulation, but she's not about to let her see that. She slowly takes in the sight in front of her, her smile perhaps growing a little wider.
The sparkling of the lower half of Queen Chrysalis’ forelegs, the entirety of her back legs and tail, and a small amount of the chitin on her back is certainly a strong juxtaposition against the rest of her matte black, green, and blue.
“I don’t know.” Twilight Sparkle takes a step forwards, frowning as Queen Chrysalis tenses up. She advances anyway, surprising the tall changeling with a nuzzle into the crock of her long neck. She tucks her legs under her in a pony loaf, bumping the sparkling legs next to her with her own shiny side. “I kind of like it.”
“You… do?” asks Chrysalis, her voice confused and hesitant. She lays down next to Twilight, trying to find what is so fascinating in the sky above.
“Sure.” Twilight sighs as she inspects her own leg. “I think it’s only temporary, though. Otherwise, the crystal ponies would look like that all the time.”
“I suppose that is some solace,” Chrysalis replies, inhaling deeply of Twilight’s love and sense of accomplishment. Odd. She senses none of the barriers she felt when she was draining earlier, as if the alicorn has intentionally let down her guard, and is keeping it down. Unlike when she tricks a pony, and must keep the connection forced open. She greedily accepts, replacing what she burned off trying to escape the Crystal Heart's fury.
“I had a few questions, if you don’t mind answering,” Twilight says after a brief pause.
“Mm,” Chrysalis says, pausing in her snacking. She’ll need her wits about her, not stuck in the euphoric haze that a full meal (not that she’s ever been full) gives her. Plus, it seems like a fair trade.
Wait, fair trade? What is she, a pony? And yet she can’t help but say, “Ask away.”
“What do you want from life?” Twilight sighs, resting her head against her folded legs. "Help me understand. Why do you do what you do?"