Pictures speak 1000 words

"H-how...? How could this happen?" Rainbow Dash walked slowly across the ruins of what used to be Cloudsdale.

To her left, she saw several large basins which at one point held enough water to produce clouds for the hottest summer days. Scattered nearby were chunks of metal, indicating not all the tanks survived their encounter with doom.

In the distance to her right, Dash saw what remained of the Wonderbolt Academy. It didn't seem so long ago that she had attended a camp there and earned respect from Spitfire as a powerful flyer. Just recently, Scootaloo had attended that very same camp under her care.

But now everything was nothing more than rubble. Cloudsdale City Hall lay still, a silent wreckage. The young flyer's arena? Reduced to a few shattered pillars. Just behind it, the Reservoir was more full of stone than water. Dash could see crags of broken building poking out from under its surface like foals poking their heads from their hiding places, hoping they wouldn't get into trouble.

Rainbow Dash continued her search. Spitfire had sent her on a mission to root out the attackers and eliminate them. Down the cloud streets she walked until she came to base of the young flyer's arena, where a figure stepped out from the rubble.

Dash recognized her immediately. There were only two mares with a mane and tail as blonde as hers, and she wasn't Applejack. She carried a thick greatsword over her shoulder, one of the few ponies strong enough to wield such a weapon without magic. On her chest and hooves, she wore the signature grey and purple armor of one of the most powerful family of ponies in Equestria, a family which boasts such members as Daring the Adventurer, Dinky the Sorceress, and even Rainbow the Dash herself.

"Derpy..."

"Dash."

"Did you do this?"

Ditzy Doo's pulled the greatsword off her shoulder and swung it at a nearby pillar. She stopped the blade just as its edge nicked the pillar, then pulled it back and struck the top of the pillar with its broadside. The stone structure exploded from the impact as though it had been shot with a cannon, sending more chunks of stone into the reservoir and leaving a perfectly smooth stump where she had cut.

"Does that answer your question?"

"Why?! Why are you doing this?"

Ditzy trotted toward the edge of the cloud island and pointed toward Canterlot. "Look, Dash. Over the castle."

Rainbow turned her head. A wild storm was growing rapidly over the mountains near the Canterlot side of the Everfree Forest, unchecked by pony hooves.

"That's... big."

"There's only one pony I know who can stop something like that, Dash." Ditzy glanced sidelong at Rainbow. "And I couldn't get your attention without doing something drastic."

Rainbow gaped at Ditzy. "Are you saying you destroyed Cloudsdale just to get me to talk to you? That's just..."

"Derpy?"

"I was going to say insane, but derpy works too." Rainbow looked back at the storm that continued to grow. "Still, if you hadn't gotten my attention, I would never have known about the storm until it was too late. Thank you, Derpy." She spread her wings. "Time to get to work."

A glint of light flashed across Rainbow's vision. She instinctively leapt to the side and rolled to her hooves as Ditzy's enormous blade crashed down where she had been standing.

"Derpy, watch it!" Ditzy pulled the sword back over her shoulder and glared at Rainbow Dash.

"Woops."

"You... You did that on purpose, didn't you?" Suddenly the broadside of the blade crashed into Rainbow's chest, blasting her into the wreckage of City Hall.

"Does that answer your question?"

Rainbow shoved the rubble away and climbed back to her hooves. "Have you gone nuts?! I've got to stop that cloud before it's too late!"

Ditzy 'Derpy' Do and Rainbow 'Dash' Do looked into each others eyes, neither flinching, neither backing down.

"No, sister. You aren't going anywhere."