//------------------------------//
// Magna Tenebris (Great 'Power') 
// Story: Princess Of Shadows 
// by DashTillDawn 
//------------------------------//

"Et superius labrum radit? Definitely not that one. Spiritus draconis? Not that one, either. Pegasus alas? Getting closer... Aha! Magna Tenebris! 'Great power!' This is the one! It has to be!" Starlight thought aloud in the dark library, while paging through the book she had 'borrowed' from Twilight. The book was titled Starswirl's Spells, and it contained just that: dozens of spells Starswirl the Bearded had left unfinished when he disappeared.
Starlight stood and guided the ominously dark halls of Twilight's castle by nothing but the dim blue light cast by her horn. At this hour, everypony else would be asleep. She, herself should have been asleep, but couldn't risk passing up the opportunity of getting her hooves on this book. It always sat on Twilight's nightstand, where she would notice if it was missing during the day. Because of this, Starlight had waited until she was absolutely certain that Twilight was sound asleep before snagging the book. Now she had to face the dilemma of getting it back in place.
When she reached the princess' bedroom door, she doused her horn, and silently twisted the golden doorknob. peering through the crack that had been created, she glimpsed nothing but pitch-black darkness. She pulled the door open entirely, allowing the little moonlight from the hall to seep into the room, which cast Starlight's shadow across the floor. The light entering the room was just enough to display the lump in the covers where Twilight slept. Creeping to the bedside, book in hoof, Starlight held her breath. She could have simply levitated the book to the nightstand, but it was evident that she was too tired to pull that off without running the risk of bumping Twilight with it. Starlight placed the book back where she had found it, and turned to leave. That was when a groggy-voiced mare spoke up, freezing her in her tracks.
"Starlight?" Yawned the Princess of Friendship.
"Yes?" Starlight responded, not knowing what else to do.
"Wh- what are you-" She yawned again. "What're you doing?" She barely managed to get out, heavily slurring her words with the unintentional accent of sleep.
"Definitely not borrowing the book you told me not to touch."
"Oh, okay." Another yawn. It was as if her body was yelling at her to go back to sleep. "You could use the extra reading." She stated in the nonsensical language of sleep. "Goodnight, Starlight." It couldn't have been thirty seconds before Twilight was snoring heavily.
Starlight finally allowed herself to let out the breath she was holding in, and quickly ushered herself out of the room, lest there be another sleep-induced conversation. As the door glided shut just as silently as it had opened, Starlight grabbed the solitary page hovering beside her in a teal aura. This happened to be the same page that Starlight had pulled from the book, just before she gave it back to Twilight. She retreated to the desk in her own bedroom, and lit a single candle to use as light while she worked. Laying out the page, she grabbed a quill with that same teal glow, and dipped the point in a bottle of ink. Her hornwriting was even worse than usual, due to the sleep depravation she was experiencing, but she wasn't about to let that stop her. This could be her big break, and she would work all night if she had to. By the time the sun began to peek over the horizon, she would have redefined her future.





Something felt off to Twilight when she clambered out from under her covers. The sun had yet to crest the hills in the distance, but the deep-sapphire sky was beginning to take on a lighter hue. Dark grey clouds loomed ominously in the background, promising a heavy storm later in the day.
Twilight struck the candle wick on her nightstand to illuminate the room, and immediately noticed what was different. The book written by Starswirl that she kept at her bedside had been moved slightly. She had a very neat method of organizing things, so it wasn't difficult to see that the book was no longer lined up with everything else that she kept there. 
Quickly snatching up the book in her purple grasp, Twilight skimmed through the pages, looking to see if anything was taken. Her worst fears were brought to life when she noticed a page had indeed been torn from the book. Worse yet: it was a page containing a very dark and powerful spell. Magna tenebris, or 'great darkness,' was not a spell to be messed with. Whoever took this page didn't know what they were getting themselves into. A new memory was slowly returning to Twilight, as well. Hadn't she seen somepony in here with that book last night?
"Starlight." She mumbled under her breath. "Starlight!"





Magna tenebras: non receperint vos. That was the final copy of Starlight's spell. The spell that would finally earn her the wings she had waited so long for. She briefly contemplated if this was cheating, but eventually decided that the deserved this. Besides, this was all Twilight had to do, so why couldn't it be just as simple for her? She seized the page from the desk, and made her way outside. This would be a big spell, and she felt it necessary to avoid collateral damage. She couldn't have her big moment ruined because she messed up Twilight's castle.
Starlight stepped outside an noticed the grey sky was making preparations to trade the moon for the sun, as it did on a diurnal basis, discounting the times when Nightmare Moon had attempted to make eternal night, and when Discord raised the sun and moon simultaneously. What was it with villains that made them want to ruin a perfectly good sunrise?
Levitating the paper containing her masterpiece of a spell a few feet in front of her, Starlight readied her magic. Her horn lit with a pleasant aqua-blue glow, illuminating her surroundings. Just as she made to cast her spell, she heard a familiar voice call her name from somewhere behind her. Upon turning, she instantly recognized the purple mare.
"Twilight? What are you doing here?" Starlight asked.
"You can't use that spell! It's not what you think it is!" Twilight called back, the urgency in her voice far surpassing the tiredness of morning. Starlight hesitated, thinking over what Twilight had said.
"How do I know you're not just trying to stop me from jumping ahead in my destiny? Trying to keep me on the path you want me to take?"
"That page holds the Magna tenebris root, which translates to 'Great Darkness.' Whatever you're trying to do, that's not the spell you want to use. Trust me." Again, this made Starlight pause. Twilight made a move in an attempt to get closer, but Starlight backed away, still unsure. Eventually, her eyes steeled with her decision.
"I don't believe you." She turned back, blasting the page with a burst of teal light.
"NO!" Twilight called in vain. The page hovered into the air, spinning rapidly. They both stared in awe, anticipating what it would do next. Unfortunately, neither of them could have predicted the spell's next move. The teal glow darkened to a deep grey, almost black- the same color as the approaching storm clouds. A tendril of the blackness surrounding the page shot out, catching Starlight, and enveloping her within. The page then disintegrated, and the darkness vanished. Starlight dropped to the ground, unconscious. Twilight sprinted to her side, not wasting a moment.
"Starlight! Are you okay?!" She nudged the unmoving mare, getting only a displeased groan in response. Twilight relaxed slightly at this, hoping that the spell hadn't worked. However, she discovered all too quickly that this wasn't the case. Starlight's eyelids flashed open, but the eyes behind them weren't her own. They were blood red, and filled with an anger and menace that struck a never-before-felt fear into Twilight. More than that, it was a sense of pure terror; that feeling that one gets upon realizing that their life is at stake. For Twilight, that may very well have been true at this moment. Starlight was on her feet in a split second, staring down the princess with that horrifying glare. 
"Starlight?" Twilight tried, doubting she would get the answer she hoped for.
"Starlight Glimmer is gone. I am Blacklight, the Princess of Shadows." She unfolded a newfound pair of wings from her sides to emphasize her point. "And you- Princess of Friendship- shall not be allowed to stand in my way." Without warning, Starlight blasted Twilight with her horn, knocking her several feet back, before skidding to a halt on her side. There was a new, searing pain coming from the side that hadn't touched the ground. Twilight grimaced from the hit, but managed to get back on her hooves.
"I was hoping you wouldn't stay down. It's more fun this way." The thing that was once Starlight laughed a maniacal laugh, readying for another attack.
"I'm not going to fight you, Starlight." Twilight stated defiantly.
"My name is Blacklight." She let loose another bolt of magic, striking Twilight square in the chest. She tumbled back again, but still struggled to her feet.
"This isn't you talking, Starlight. Don't let the darkness take control." The princess gasped. For a brief moment, the purple in this thing's eyes became visible. Starlight was in there still, fighting to break free. She closed her eyes and shook her head. When they reopened, they were that vicious and evil shade of red again.
"My name isn't Starlight!" Spat the monster controlling her friend, once again blasting Twilight, who simply took the hit. It hurt even more than the last, but Twilight refused to be pitted against her friend like this. It was getting increasingly difficult to stand again, but she did it anyway, ignoring the building pains in the places where she had been struck.
"Do something, you imbecile! Fight back!" Screamed Starlight.
"By letting you get taken by this evil, I have already failed you. I have already hurt you. I'm not going to do it again."
The thing yelled in frustration, wanting more of a battle than an execution. However, that wasn't enough to stop it from blasting Twilight again, catching her in the ribs. The pain shot through her entire body, knocking her down again. Blacklight stood over Twilight, readying one last shot. The killing blow.
"Pitiful; you couldn't even put up a fight. What a shame." It spat.
"I'm not hurting my friend, so you may as well finish me off. Just do me one favor: look me in the eyes when you do it."
"Ah, the dying wish of a princess. Sure, I'll look you in the eyes. I'll make sure the last thing you see is pure hatred." She wound back, her horn emitting a bizarre and foreign black light- if you could even call it a light. As she brought down her horn for the final attack, she froze. After a brief moment, she had a slight seizure, letting out a screech of pain an agony. Purple fought red within her eyes, as darkness fought light in her mind. Starlight had come, kicking and clawing, in an attempt to regain control, rather than sit idly by as this monster murdered her friend. Upon realizing the mental war, Twilight did everything in her power to assist Starlight from the outside. 
"Don't let that thing control you, Starlight! Fight it!" Twilight offered words of support, while wracking her brain for any potential spells that could evict the darkness. If Magna Tenebris had caused this, then perhaps the polar opposite- Lux Splendida- could save her. Twilight thought rapidly to piece together a reversal spell, while Starlight struggled for control of her own body. Then Twilight figured it out. [iMagna tenebras, non receperint vos! That must have been the spell that Starlight used. Substituting one root for the other would then give her the solution.
"Lux splendida, non receperint vos!" Twilight yelled aloud while casting the spell. A beam of purple light shot from her horn, causing Starlight to topple over. In the struggle for possession, one last bolt of mana left the mentally-split mare's horn, striking Twilight at the base of her own horn. Though there were only two ponies present, three screams of agony could be heard. Then the action was over. Both mares lay unconscious, only feet from each other. That was when the thunder started.





Starlight awoke to raindrops tapping her eyelids. Judging from how she was drenched and freezing, she guessed that it must have been raining for several hours. She clamored her way onto her hooves, groaning from the soreness and stiffness that ached in her muscles. Once upright, she noticed another pony laying not far from where she had been. A familiar pony, at that...
"Twilight!" Starlight gasped as the memories of what happened came flooding back. She closed the gap between them near-instantaneously, concern overriding anything and everything else within her. Kneeling by her friend's side, she gave the purple mare a gentle nudge.
"Twilight? Twilight, wake up." When she didn't receive a response, Starlight looked to the princess' chest. What she saw were burn marks, where Twilight had defiantly taken her magical beating without wavering; a feat of remarkable honor and discipline. She did not see, however, the usual rise-and-fall pattern- the telltale sign of life. Starlight bent over, placing her face millimeters from Twilight's. She should have felt and heard a rhythmic breathing, but instead found nothing. Tears welled up in Starlight's eyes, mixing with the rainwater in an attempt to blot out her vision. Starlight didn't even blink them away. If her vision were blocked, she wouldn't need to see Twilight's fate, which came as a result of Starlight meddling with her own destiny.
It was ironic, in a way: not more than two years ago, Starlight had messed with the timeline to disturb Twilight's destiny, maybe even kill her. Now, here that same mare was, lifeless in the rain- exactly what Starlight would have wanted. But now, the only thing she wanted was to see her get back up again.
Filled with total despair, Starlight laid down next to her friend's static body, and wept. She hated herself for her inability to save Twilight. She hated herself for casting that spell. She hated herself for not listening to her friend. She hated herself for thinking that this was a good idea. She hated herself just for existing. That was when Twilight let out a faint groan.
"Twilight?" Starlight whispered, thinking it was only her mind playing tricks; reliving old memories.
"Ugh... W-what h-happened? D-did we do it?" She barely managed to get out, teeth chattering from the freezing rain. Now the tears of sorrow in Starlight's eyes turned to tears of joy. She caught the princess in a sudden, tight embrace.
"No, Twilight. You did it."