King Sombra is an Edgelord
Princess Twilight Sparkle charged her horn, releasing another powerful magical blast that obliterated the dark crystals in front of her. Flapping her wings to take to the air again, Twilight flew forward, followed by her five best friends, as the charged down the corrupted hallways of the Crystal Palace. The normally glimmering walls were dulled to black, and an aura of despair hung about the entire building.
King Sombra, despite the Council of Friendship's best efforts, had managed yet another resurrection, and had immediately set out for the Crystal Empire. Cadence and Shining Armor had fought him as best they could, but in the end, they, along with many other crystal ponies, had fallen victim to the mad king's mind control magic. Even Flurry Heart was brainwashed. Yet, before she'd fallen, Cadence had sent out a message to Twilight, who'd rounded up the Council of Friendship once more to take on their recurring enemy.
The journey to the palace itself had been perilous, mainly due to Sombra's army of ponies under his thrall. Nopony wanted to hurt them, seeing as they were simply being manipulated by Sombra, and were good ponies normally. Fortunately, Twilight had prepared this time, bringing along Celestia, Luna, Starlight, and the Pillars of Old Equestria. They were currently keeping Sombra's army busy, while Twilight's team rushed through the palace to defeat Sombra before it was too late. The only other obstacles were the series of magical traps laid out by Sombra along the way.
Rarity made another shriek as another long, black crystal spear erupted from the wall, narrowly missing her. Applejack was quick to rush to her friend's aid, shattering it with one powerful buck. Pinkie casually bounced along the path, occasionally ducking or jumping upwards to avoid every spear thrust. Twilight, Rainbow, and Fluttershy were safer as long as they stayed in the air, but still had to contend with busts of Sombra that breathed purple fire at them up above.
"We're almost there!" Twilight informed the others, ducking under a fireball. "The throne room is just up ahead!"
"Sounds good to me!" Applejack responded. "I've got a lot of pent-up frustration to deal out on Sombra!"
Everypony charged together, the throne room doors approaching faster and faster. Twilight built up the magic in her horn and fired, a magenta beam hitting the doors dead-center. Sombra had laid a complex magical lock on them, but it was no match for Twilight's expertise. With a blinding flash of white light, the doors burst open, revealing the throne room.
Just like the rest of the castle, Sombra had distorted the throne room almost beyond recognition. The once calm, clean crystal surfaces had been replaced with ugly, jagged spires of black. Cadence and Shining Armor both stood by the throne, heads covered with dark helmets, their eyes glowing green beneath, their coats dulled and darkened. The Crystal Heart sat just above the throne, pierced by several long spires of the black crystal. Sombra himself was perched atop the throne, grinning like a mad stallion, showing off his sharp fangs. Flurry Heart was perched on his shoulder, her eyes green and distorted like all under Sombra's control.
Twilight flew downward, landing directly in front of the throne. "King Sombra!" she shouted, pointing at the shadowy pony with one hoof, "Your terrible reign has come to an end!"
Sombra threw back his head, jostling his shadowy mane. "Ah, Princess Twilight. Your defiance is so adorable! You actually think you stand a chance against me!"
"Well, to be fair, we beat you twice before," said Pinkie. "I mean, it's not unprecedented—"
"Silence!" Sombra snapped, pounding one forehoof on the throne. "I am the great King Sombra! The Crystal Empire rightfully belongs to me! And you shall never take it!"
He pointed with his hoof, directing Cadence and Shining Armor to attack. Flurry Heart took to the air as well, flying towards her aunt with rage in her eyes.
The six friends didn't back down, however. Twilight, Rainbow Dash, and Fluttershy floated down, joining hooves with Pinkie, Rarity, and Applejack, forming a circle of ponies. Twilight ignited her horn, as a faint white glow appeared over the other five. Just before the brainwashed rulers of the Empire managed to reach them, Twilight released a pink pulse of energy, coming out in a circular wave, that washed over the opposing ponies. When it touched them, the eyes of Cadence, Shining Armor, and Flurry Heart all suddenly lost their green glow, turning pure white. The helmets on the heads of Cadence and Shining Armor shattered, and all three ponies fell unconscious, though Rarity managed to catch Flurry Heart with her magic before she hit the floor.
Sombra was, needless to say, not amused. "Clever," he muttered under his breath.
Twilight smiled. "I drew on the magic of my friends to shatter your mind control. One shot only, but I'd say it did it's job."
"Not that we really need to be afraid of you," Pinkie said, rather matter-of-factly. "I mean, come on. You're the most edgey bad guy we've ever faced. Seriously, what's so scary about you?"
Sombra had opened his mouth, possibly to issue a scathing response to Twilight's last statement, but Pinkie had spoken before he could. His expression morphed from one of fury to one of confusion in a single second.
"...what?" he finally asked, looking at the pink earth pony.
"Really, you've got the whole red and black color scheme going on," Pinkie continued, waving her hoof as if to demonstrate, "you have a curved red horn, something no other unicorn has, you've got freaking fangs, and you put some sort of curse on the crystal ponies so they forgot everything before you ruled over them? Who are you trying to impress, the fanboys? You wouldn't look out of place in angsty teenage Starlight's bedroom."
Sombra clenched his teeth. "I don't know who these fanboys you speak of are, Pinkie Pie, but you would do well to avoid insulting me! I am darkness incarnate! Your opposition to me shall fall like a chaff in a storm!"
"Yeah, Pinkie," Applejack whispered, nudging her friend, "we still kinda have to defeat him. Maybe don't make him too angry before we actually fight?"
Pinkie ignored both of these warnings, however. "Oh, yeah, you are the darkness. Oooooooh, real scary. Let me guess, you also have a 'tragic' backstory that's supposed explain why you're evil and make us feel sorry for you, even after all the terrible things you've done? You're just a tortured soul deep down who needs somepony to hug him or some crap like that?"
Rainbow Dash snorted involuntarily. "I never thought of that," she said. "We never actually learned anything about your origin story."
King Sombra growled, rising from his throne. "If you truly desire to know," he began, "Over one-thousand years ago, I was the most talented magical prodigy in the Crystal Empire. I was destined to be our leading sorcerer, capable of things nopony else would even dare to attempt. But when I began to experiment with dark magic, those self-righteous fools banished me! Cast me out to wander the frozen wasteland for eternity! I vowed to make them all pay, drawing on the forces of darkness to become the something more than a unicorn, to become the living embodiment of shadow you see before you—WHY ARE YOU LAUGHING?!"
Indeed, Pinkie had doubled over and was howling with laughter, as was Rainbow Dash. The others weren't cackling quite as hard, but they still had oversized, comical smiles crossing their faces, and were clearly struggling to hold back chortles. Even Twilight had pressed her forehoof to her mouth to try and suppress the laughter.
"Seriously?!" Rainbow managed to wheeze out through her guffawing. "That's your origin story?! Pinkie's right, you really are an edgelord!"
"I know, right?!" Pinkie chuckled back. "'Wah, my mom and dad didn't like when I dabbled in the dark arts! I'm gonna kill 'em! Oh, please ship me with your obvious author avatar OCs!'"
"I...WHAT...YOU..." Sombra sputtered, drops of spit flying out from between his lips, as if he was desperately searching for a response. His already red eyes were completely bloodshot with fury, and his forehooves flailed on his throne, pounding away at the crystal. Twilight, through her suppressed laughter, noticed that tiny bolts of black electricity were beginning to spark from the tip of his horn. What was worse was that the bolts were increasing in size.
"Everypony duck!" she yelled. The other immediately obeyed, diving behind some of the crystal spires, though Rainbow, still in the thralls of hilarity, had to be yanked down by Fluttershy.
Sombra's mouth opened, letting loose a furious scream as he reared up on his throne. The dark magic around his horn continued to swirl, building up an incredible amount of energy. The green glow appeared around his red eyes, and cracks suddenly began to appear on his horn. With one final roar of agony, King Sombra lost control of his growing magic, as rushed downward into his body, turning him into the same black crystal he'd covered the castle with.
Then his body exploded, spraying shards of the evil king all over the throne room.
Twilight and her friends poked their heads out from behind the spires, glancing all around the room to make sure Sombra wasn't reforming.
"Well," said Applejack, "that was...something, alright."
"Yeah," agreed Twilight. Then a question occurred to her, and she turned to Pinkie Pie. "Hey, Pinkie. How'd you know calling him an edgelord would make him so angry he'd blow himself up?"
Pinkie shrugged. "Edgelords hate facing the fact that they're edgelords. Everypony knows that." Then she happily began bouncing towards the exit. "Who wants to get ice cream to celebrate?!"
