Chaos and fire

“How can you act like this, Luna!” yelled Celestia. “You’re the princess of Equestria, not a capricious filly !”

“Am I ?” asked Luna, raising her eyebrow. “I think I’m in charge of nothing more than a sleeping land, sis’. After all, it’s how Equestria works, doesn’t it? Ponies playing and enjoying your days and then spit on my nights !”

All under the princesses, the fire rose in intensity.

“Luna please,” requested her elder sister. “The forest is burning! Can we talk about our problem later ? We have a country to protec t! It’s our duty !”

“Don’t talk me about duty, Tia !” screamed Luna, feeding the blaze. “I know royal duty as much as you do.”

“Yes. Because we rule together. Remember ?”

“Hah !”

Luna’s voice took a mocking tone.

“Together ? We rule together ? That’s new ! We’re not co-rulers, Tia, we’re revolving princesses ! I have never seen one of our subjects! Never! You’re out all day, meeting ponies, being loved...me, at night, I stay in the castle and I see nopony ! Nopony ! Do you know why ? ‘Cause everypony is sleeping and nopony sees my gorgeous work !”

Tears flew out of the eyes of Luna but disappeared immediately, evaporated by the heat of fire.

“Luna...”

For the first time since the beginning of the argument, Celestia’s voice became sweeter, almost suppliant.

“Please calm down. It’s not too late to fix those mistakes. It’s never too late.”

A tree collapsed on itself with a terrible noise. But none of the sisters noticed that, each was focused on the other.

“So let this night be,” said Luna. “For one day, let the night be.”

“I can’t Luna. And you know it. A night can never be longer than it has to be. It’s the rules. Our rules.”

“I don’t give a damn about the rules!” yelled the alicorn of the night. “The choice is yours, sis’: you can let me hold this night for one complete day, or fight me.”

“I’m your elder sister. I would be happy to give you this present, Luna...but I’m also the ruler of Equestria, and the harmony of the ponydom is above all.”

As she was speaking, six colorful gems appeared around her. Luna easily recognized the Elements of Harmony. She understood as well that the time of the break-up between the two sisters had arrived.
No matter who won, Equestrian ponydom would lose a princess.
Luna’s coat turned black and her mane turned violet as she succumbed to anger and bitterness. Surprised by this transformation, Celestia didn’t react immediately when her sister attacked her.
Hooves raised, Luna jumped on her elder, only to be stopped by a shot from the Elements of Harmony.
Luna grunted before attacking again. Celestia dodged.
This game went on for a little while, until Luna decided to attack for good. Her jump was mixed with an offensive spell, forcing Celestia to defend herself.

She recognized Luna’s spell: it was one of destruction, one of the most powerful in the alicorns’ arcane. If she was unable to stop her sister right now, this spell could blow up a large part of Equestria. She was forced do to something.
Reluctantly, the elder unleashed the power of the Elements of Harmony against her own sister. Luna yelled a long and terrible scream when the rainbow hit her.

In a violent magic explosion, the Elements of Harmony neutralized Luna and teleported her far away from Equestria.
Alone in the burning forest, Celestia summoned large dark clouds and used their rain to stop the fire.
When the water hit the flames, the princess let her sorrow overcome her. She had lost Luna.
Her own little sister, becoming evil. It was unbelievable. She couldn’t defeat Discord without Luna and now...
Now, even the Elements of Harmony seemed to disapprove of her act. The gems lost their shine and their color slowly perished. In a few hours, the jewels would become rocks.

Celestia looked at the moon, crying when she realized that her little sister would be alone up there for a thousand years.
If she was only a big sister, she would have allowed the moon to stay up, to see Luna and apologize to her. But, like she had said a few minutes earlier, she had a royal duty...
Celestia lowered the moon and raised the sun. The sky was blue and the star shiny, but deep in the princess, her heart was as devastated as the ashes of the Everfree forest...