"How long till they break through?"

I'd say about a month, mabye less. You're not going to have enough time to transform this pathetic world into a nation ready for war. You can hardly train one of them!

"Look she just needs to be...disciplined a bit more."

Or perhaps literally whipped into shape. Loyalty needs to know where her priorities are, you fight for the majority, if losing all your friends means saving an entire planet then so be it!

"She only acts by her nature, she just needs to learn what's at stake here."

Nature. Bah! There's nothing natural about this world. It can barley function on its own without the intervention of the ponies.

"We will get this figured out, we won't let them prevail this time."

We? No, this is as far as I take you, if they come and this planet is imploded then fine, not my concern.

"Very well then, it was...helpful."

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After day three of training, the princesses and Rarity were sent to different locations to complete their assessment. Of course Rainbow Dash protested against it, but Guardian kept saying that "Remaining here to train would be pointless. Her talents would prove useless in combat so therefore she is being sent to Canterlot were her skills would be helpful."
As for training, it was rough on all of them, Rainbow Dash most of all. It wasn't the physical challenges no she passed those fine, it was the constant arguing with Guardian that put her on cleaning duty in the new training base he constructed. She was always fighting against his authority. She felt that Guardian didn't have the right to order them around. While Rainbow didn't fully understand the gravity of the situation, she still felt that the constant shouting and bossiness was unnecessary. Rainbow Dash had to watch Applejack and Twilight become so exhausted from the exercises Guardian makes them do. Pinkie and Dash could handle them just fine but watching Guardian push them so hard to their breaking point was too much for her to bear.

Then there was Fluttershy.

-----------------------------------

Fluttershy stood in the middle of a snowy plain. Explosions were going off all around her. Projectiles were falling from the sky and hitting the ground, throwing dirt and snow everywhere. Groups of unicorn soldiers were firing bolts of magic at an unseen enemy. Large metal things flew overhead, one getting hit by something and going down in a ball of fire. In the distance Fluttershy could see the Crystal Empire. Floating shapes surrounded the spire, enormous cannons firing at a massive, sinister looking airship approaching the empire from the west.
Fluttershy forgot why she was there the moment she was...deployed? She didn't even know what that means. She wore a nurses cap and heavy saddle bags containing medical supplies. She guessed she was supposed to treat someone, but so many ponies lay dead already.
She was frozen in place by fear, all the noise and death was maddening. Fluttershy couldn't remember why she was there.
The airship was directly over the city now, a faint glow was coming from its underside. The glow intensified and a beam of energy struck the Crystal Empire in a blinding flash of light. Somehow, Fluttershy knew it was her fault, she hadn't acted quickly enough. Her cowardice brought the death of over a thousand innocent lives.
The light expanded and engulfed her, then it was all over...

Again.

-----------------------------------

Rainbow Dash shot up out of her bed at the sound of an air horn. She looked around at the bare metal walls of her dorm and sighed. Her, Twilight, Applejack, Fluttershy, and Pinkie had eaten and slept at the training base, they hadn't stepped outside the facility in two weeks.
Rainbow Dash looked at the blank, depressing walls. Her room wasn't even that big. There was the bed against one wall, and a few feet of floor in between the bed and the door, and an inch from the other wall, and that was it. Rainbow was fed up with it. Guardian had no place to be ordering them around, keeping them in this building. It was practically prison. The worst was his boring lectures, Rainbow always fell asleep during those. At first she was afraid she missed something important, but now the pegasus could care less about what he had to say.
Guardian was shouting at them to get up now. Rainbow Dash could hear the others getting up, but Dash herself decided she didn't have to listen to that control freak anyway. In fact, now she wondered when was he put in charge.

He took charge because he has the most experience with this enemy. You are the most unbelievably idiotic individual I've ever seen.

Rainbow Dash was now fearing for her life. The voice she never thought she would hear again was back, and he was mad.

I think it's high time you learn what happens if you continue to fight like this.

Rainbow Dash had three visions of mass destruction. The first was of Canterlot, now a pile of rubble scattered at the base of the cliff. The second was of the Crystal Empire. The grand spire had collapsed and most of the city was on fire. The last and most horrifying vision was her friends lying dead in a burning Ponyville.

The first two visions had appeared in rapid succession, but the third and worst vision was still happening. The chaos of war was distant, giant floating shapes in the sky firing at each other, smaller shapes zipping around the massive ships.
Rainbow Dash stood on the edge of a ridge, with a perfect view of her friends unmoving bodies. They lay in a desert, Rainbow guessed they were near Dodge Junction. There wasn't anything else around them, just more bodies and piles of burning mechanical wreckage.

This is what your arrogance will lead to.

Rainbow Dash barley heard Him, her thought process had been almost stopped completely. The horror in front of her had shocked her beyond words. All she could utter was a small, short sob.

She hadn't cried very many times in her life. Only twice she can remember when she was a filly. There was the first loss, the soccer game that would've taken them to the finals. They were tied with the other team, then they slipped past defense and got in a buzzer beater. She cried then.
The other time was when her grandfather passed away. They had always been close. It pained her much when he died. So she cried.

Both times however, Dad had been there to comfort her. Dad was the greatest. He was the most important pony in her life right next to her friends. But this time he wasn't there. No one but the evil being showing her this terrible sight.

Rainbow was full on crying now. She lay face-down in the dirt, spasms wracked her body as she wept for her failure to save them.

The visions ended and Rainbow Dash returned to the real world, tears still fresh in her eyes. Sitting on her bed across from her sat Guardian, the look of a sad, old man in his eyes.

"I hope you understand now why I push you so hard." He spoke softly, his voice barley audible.

He looked down, unable to meet Rainbow's eyes, "This is what has to happen. Discipline is the key. You have to be ready for the road ahead, and it ain't a pretty one."

A single tear rolled down his cheek, "I've fought them before, defending other worlds against them. But I failed every time. The amazing people I've met during my existence burned along with their entire planet. I don't want that to happen again."

Niether do I...but for very different reasons.

Guardian looked back up and saw a smile spread across Rainbow Dash's face. Now that she fully understood what was at risk, she was willing to give her life to save them all.

"It's okay...I'm with you now."

Author's Notes:

Oh the feels...