Arcane Shift

And there she lay, a breathless filly.  Breathless?  No, lifeless was more fitting...

"A flying incident, you say?" Twilight Sparkle asked.

"Yes," answered Rainbow Dash, on the edge of tears, "she... she finally got off the ground, and-" the rest was unintelligible through Rainbow Dash's sobs.

"Is there anything you can do?" she asked her friend, desperate for an answer.

"There is... one thing..." Twilight hesitated in revealing this.  "A spell, used long before the time of Celestia and Luna; a spell used in times of strife, times of war.  One that I came across in my studies, that Celestia warned me against ever using..."

'DO IT!" Rainbow Dash shouted, "PLEASE!" she paused for a moment, "Please save Scootaloo's life..."

"A spell that can bring a pony from the edge of death..." Twilight looked grimly at the dying filly.

"Never use this spell, Twilight Sparkle!" Celestia said sternly, "Even if it is life and death!"

"B-but..." the purple filly had nothing to say.  Celestia had never spoken to her like this...

"It hasn't been used since the Dark Times, and I intend to keep it that way!"

Two options lay before her: defy her teacher, or let Scootaloo's life fade away.

But was the second really an option?  Staring at the body before her, Twilight couldn't help but think of what Rainbow felt, or what Scootaloo's friends would feel.

"Life is a fleeting thing.  Lives are short, and lives are long.  But death is not something to be accepted, but something to run away from, to fear and hate and regret," Twilight quoted Starswirl the Bearded.

Suddenly, the room started glowing a purple hue.  The hue became more and more prominent, until everything yellow in the room seemed to glow black.  Books fell off the shelves, and Rainbow Dash stopped sobbing into her hooves to see what was going on.  Twilight's horn glowed brightly, and Rainbow Dash felt hope again, a feeling she thought she'd never feel again.  Hope for her future - for Scootaloo's future.

Then, a bright white flash.  Rainbow Dash covered her eyes.  When she looked up from her hooves, this is what she saw: a messy library, and a sleeping filly.

When the sleeping filly woke up, she looked around in confusion, but was nonetheless happy that her idol, Rainbow Dash, was sitting next to her.

But Dash could only wonder one thing: "Where in the hay is Twilight?"

Rainbow Dash, Scootaloo, the library...  These all vanished in front of Twilight's eyes in a bright flash of light, brighter than her own magic.  Surprisingly, she wasn't exhausted.  She was... invigorated!  Ready to fight!

WAIT!  ...Fight?

When she was no longer blinded, she looked out in front of her.  Some sort of... shop?  The shopkeeper tried to hand her a pair of boots and two red vials, but they quickly faded into the air, the strange golden particles attaching themselves to Twilight before vanishing.

She looked to her right, and saw a large, floating, blue crystal.  To the left and right of it were two paths, and a forest between them and her view of the crystal.  Nearly ignoring all of this, she felt compelled to move forward, and around the crystal.  Then, a third path came into view, in between the two other ones.  She felt compelled to move down this path.

As she walked, Twilight noted others around her, they seemed like... humans?

A man with brown hair wearing armor made from gems and a boy with dirty blonde hair and dirty clothes with a gem in one of his gloves went the the right.  A woman with purple hair, pasty-white skin, and pupil-less eyes went left.  A shirtless man with a cloth covering his eyes, and his solitary patch of hair tied into a pony tail walked beside her into the middle path.

"What's going on?" Twilight asked him.

"Strike firmly," he answered simply.

"What does that-?" before Twilight could finish, the man wandered off to a path branching off the main one.

There were two towers along the path, another one just before, and two around the large crystal where she had started.  When she reached the second tower, she felt compelled to stop.

The path kept going, but she stopped in her tracks.  Beyond her was another tower, but it seemed a bit more... purple?  And also felt sinister to Twilight, almost scary.

There the purple unicorn waited.  Waited?  But for what?

Then, several small creatures - some bearing armor and weapons, others not - came down the path.  There were six in total.

Something similar happened further down the path, except the creatures were purple, unlike her side's blue creatures.  Then, when they met half-way between the two towers, they began fighting.  Those in the front used their weapons, those in the back used... magic?

"W-what are you doing?!" Twilight demanded of the creatures.  They didn't answer.  They didn't seem intelligent enough to understand her.

A little girl with red hair came strolling down the path towards Twilight.

"Good, maybe she can-"

Suddenly, the girl shot a bolt of fire at one of the blue creatures, and it fell down, lifeless.

"-help..." this disheartened Twilight.  The little girl no longer looked innocent, but menacingly stared at Twilight, occasionally launching bolts of fire at the blue creatures.

"Hey!" Twilight said, "You're hurting them!  Stop!"

With that, she charged at the little girl, teleporting to her when she tried to launch fire at Twilight.  The unicorn quickly turned around and kicked the girl into the purple tower.

"She seemed barely phased, "Don't make me hurt you..."

Suddenly, Twilight felt the fire surrounding her.  The girl had released a small wave of fire, and was launching a large bolt of it at Twilight.

Twilight knew this was the end.  She couldn't get out of this one.

Rainbow Dash... Scootaloo... knowing that she had saved a another life, she was willing to give hers to keep the world in balance.

She had stolen one filly from Death, and had to give back another...

She felt conciousness break away from her.

With her last breath, she said, "I'm sorry..."

Life left her body.  But not for long.

She was alive!  Back at where she had started, she felt as good as ever!  Invigorated!  Ready to fight!

Fight?

Well, she understood something in that moment that not even her great mind could deduce: no one on these fields die.  They merely are re-summoned to the world by some powerful magic.

"You're not getting away this time, little girl..." having felt death, and felt awakening, Twilight had no reservations about ending that little girls life.

Ending?  More like temporarily suspending...