Disclaimer: My Little Pony is the properties of Hasbro. This is a non-profit work made by an independent contractor outside of the official company's notice intended for non-profit entertainment and speculative purposes only.
By Darkryt Orbinautz
In Sombra Cadam
It was in the Ponyville library, where Twilight Sparkle, the local librarian and her six friends resided, celebrating their recent victory over the shadow king that threatened the Crystal Empire. They'd chosen the library as it had been the most spacious of their homes, so it would be the ideal place for the world-rocking experience known as a party hosted by Pinkie Pie.
"Hey! Hey! Hey everypony LOOK AT ME!" Pinkie instructed, doing...something on top of a table. It involved the punch bowl, so it couldn't have been anything good.
"Are you looking? Are you looking!?"
"Yeah, Pinkie, we're lookin'." Applejack assured her, despite evidence to the contrary mounting.
Rainbow Dash was flexing her muscles, Rarity was drinking some of the punch, and Fluttershy was cowering, trying to make sure nopony tried to drag her into a game.
"Hey..." Spike said, noticing Twilight's...dullness. "You all right? You don't seem as happy as you were on the train ride."
"I'm not, Spike." Twilight answered. "Um-wait, no, I don't mean it like that- I'm still happy. I'm just...less happy. My happiness faded with the day." Twilight gestured to the windows.
"Okay...if you say so." Spike didn't seemed convinced, but he dropped the subject.
After Pinkie tried to make a trick (and Rarity attempted to keep Pinkie from too big a mess) Twilight started to gather everypony up and try to convince them to leave.
"Oh, must we?" Rarity whined. "I've been having the most delightful time!"
"Yeah!" Pinkie agreed. "Can't we keep the party going a little longer?"
"Okay, okay..." In the face of all her friends insisting, Twilight was powerless to resist and consented. "But keep it quiet, okay? I'm going to bed early."
"Okay!" Chorused through them, each promising to keep it quiet so Twilight could get some well-earned rest.
Twilight put down her punch cup on the table and began the trek upstairs. Each step to her seemed more...taunting then the last, each one being another obstacle standing between her and what she wanted at the top of the library inside her room.
But it wasn't sleep she wanted.
Earlier today, Celestia had shown her a magic spell that glowed black, no matter who was casting it. Unusual, as normally, unicorn horns glowed with a magic color fitting the pony using them, even if they were performing another pony's spell. She used that spell today inside the Empire of Crystal, attempting to locate a powerful relic known as the Crystal Heart to defeat King Sombra.
And it felt...amazing to use that spell. Pure, unadulterated bliss, uncensored and raw.
Finally making her way into the room, Twilight locked the door behind her and began skimming her way through the various drawers smattered about her room, where papers and tiny research items - like the prism she had been looking for, were stored.
For those unfamiliar, a prism was a small crystal that made a rainbow pattern when light was shone through it.
Twilight placed it on her desk with her hoof and began charging her magic.
Her black magic that made her eyes glow green and her irises serpentine and red. She fired the black of black energy at prism, but nothing happened. That was okay: nothing was supposed to. She just needed something to channel the magic through. It felt fantastic, using that magic trick Celestia had shown her.
Twilight looked around in a panic. That sounded like King Sombra! But it couldn't be-! They had defeated them with the magic of the Crystal Heart!
"King Sombra! It's not possible!"
"No...It's not." Sombra's hissing voice agreed with her. "But magic makes many things happen."
Twilight looked around. "Where are you? You can't still be here! I saw the magic of the Crystal Heart tear you apart!"
"I'm not here." Sombra told her. "You're only hearing my voice because you used my magic."
"Your magic?" Twilight questioned, now fearing for her life. "What do you mean?"
"Celestia...showed it to you. She resists it. You haven't."
"What are you talking about!?"
"Hmm...hmm...hmhmhmhm hahahahahahaha HA HA HA HA HA HA HA HA HA HA HA!"
A swoosh came from the window, but when Twilight looked at it, there no was nothing there to speak of.
"Hmm...okay. That was weird." Twilight noted as she turned back to the prism. She put her hooves to her mouth and let out an immature giggle as she started thinking naughty little thoughts.
She prepared the trick again, her horn glowing black as she blasted the prism again.
"Eeee-hahah Heeeeheeee!" Twilight giggled uncontrollably and bounced on her hind legs, blasting the prism again...and again...and again...and again...
"~Haaaaa~" Twilight moaned, tuckered out from the repeated usage of magic, collapsing against the deck with.
"I thought you were a smart pony, Twilight Sparkle." King Sombra's voice said...although given how it was speaking in more then three-word sentences, Twilight was beginning to question the idea that of it being Sombra's. "Surely you realize by now...?"
Twilight's eyes widened as she made the connection.
She hadn't resisted something Celestia had...and that something...was using the black magic!
"No, no." Twilight muttered, more to herself then anypony that might've been there whom was not. "That's- not possible...you can't get..."
Twilight fired another black blast at the prism, a giggle escaping her lips again the sensation.
"You can't get...addicted to using certain types of magic."
Twilight looked at the prism, which had done nothing but sit there and take her merciless pounding on it like a stray dummy, trained by years of bucking to take hits by aspiring boxers. She nervously picked it up in her hoof and examined it.
Twilight fired another blast...without even meaning to.
"I guess you...can." Twilight realized with shock. She narrowed her eyes at the prism. Her demeanor instantly became callous and cold.
"You..." She curled her hoof around the prism and shook it in her hoof. "You're not enough..."
She blasted the prism one last time...which turned it into a black crystal- just like the ones the King's magic produced when it was at it's peak.
Twilight dropped it in horror and fled to the cover of her blankets on the bed.
"I'm...I'm not becoming addicted to using Sombra's magic! I'm- I'm just excited about using a new spell, that's all!"
Or so she led herself to believe over the course of the night, lying restless in the mattress designed for letting her rest...
Author's Notes for "In Sombra Cadum"
Well, that was fast. Not even one day since the new episode's out, and I'm already writing stories about it. Oh well. I know I'm not the first, so there's that.
This story derived from an idea I had as I was speculating what would happen in the episode while watching it.
I maaaay continue this story...or maybe I won't. Who know!? Depends on whether or not I can come up with an idea.