Dark Empire

"Hold on, girls, it's comin' loose!"Applejack growled as she heaved against the side of the inner tower. After getting in they had found a loose piece of walling, and Applejack had been trying to push it free.
"Hold on Applejack, let me try something."Twilight motioned for AJ to step away, eyeing a boulder. Using magic, Twilight lifted the boulder.
"Ah see where yer goin' with this."Applejack stepped back. Turning her head towards the loose wall, Twilight sent the boulder smashing into the wall, and the loose section easily gave way. Twilight moved the boulder aside and let her friends through.
"Well, we got to the Palace. What now?"Fluttershy asked.
"We get in and get to the tower."Twilight answered.
"AND search for survivors."Rarity added. The four ponies headed up the cracked ground to the large doors. They expected to be able to open the doors, but when they heaved against it it didn't budge.
"Is it locked?"Applejack asked.
"Eh hem."Rarity looked to Applejack, pointing to the smashed lock, back down near the fallen tower.
"Oh."Applejack blinked.
"There might be a barricade."Twilight suggested, as this was MOST of the door. The rest was up near the palace's original base. Twilight peered through the gap in between the doors. No form of barricade, not even a pile of debris to hold it shut.
"Nothing back there."Twilight stepped back.
"Uuuh, Twilight, I found out why."Fluttershy called. She pointed to the base of the damaged door. It was stuck tightly in a groove dug into the ground when it landed.
"Well, there's no gettin' in through there."Applejack noted.
"I don't know any other ways in, and if there were they'd be up by its old base."Twilight stroked her chin, thinking.
"Maybe there's something up there, like a boulder we can push down to break through a wall."Fluttershy suggested.
"Fluttershy, you're a genius!"Rarity grinned.
"But even if there IS something up there, how will we push it down?"Twilight wondered aloud.
"Eh hem?"Applejack stamped a hind hoof.
"Oh, ok ok."Twilight smiled.
"So it's decided? We go up and push some boulder down?"Rarity asked.
"It's the only plan we have."Twilight answered.

~~~

"Twi? How long is this gunna take?"Applejack asked as she bucked another creature down the steps to the original base.
"Just...hold...on!Girls! Move!"Twilight answered as she yanked a boulder free from the large pile blocking their path. The four ponies jumped to the side, leaving several of the oblivious creatures to get crushed by the rocks, leaving just flesh and shattered bones behind, masses of blood pouring from the mangled corpses.
"Come on, everypony! Let's clean up the rest of 'em!"AJ grinned as she bucked a slightly confused, but attacking creature back down the steps. She hurled a rock down at it, and it hit it hard in the throat. It choked and scrabbled at the rock, which, due to some sharp parts, had jammed itself in its throat, and the scrabbling just made the wounds bigger, until it accidently tore open its throat, letting the rock, a piece of esophagus and a large amount of blood to pour out. It stumbled and fell back from shock, happening to land on an ally's sword. The now-blood soaked creature dropped its sword and attacked, leaping at AJ, but Twilight repelled it by sending a magical shard plummeting through its chest. A hunk of its heart flew out the back and the creature was already dead by the time it hit the floor. The shard exploded, shredding it and sending, limbs, flesh and organs flying in a massive explosion of blood. The remaining two screeched at the four ponies before retreating, now knowing that these four were superior. One of these two didn't get too far after a white horn flew through its chest. Rarity threw it up and threw a force spell at it, launching it off into the far lower Canterlot.
"Well, girls, we can go further now."Twilight smiled.
"Aren't you a little...shocked at the fact you killed that thing?"Fluttershy asked.
"Well, yeah, but now's not the time for that."Twilight answered.

~~~

The four ponies had reached the top of the steps, and now looked over the remains of the Palace's original base. Scattered around and through it were multiple dead Royal Guards, along with several dead creatures.
"Looks like they put up a real fight."Twilight blinked.
"Yeah. Too bad they didn't win."Applejack added.
"Or lose."Rarity noted, looking at the fact there were no surviving creatures.
"Yeah, or we'd have another fight on our hands."Fluttershy responded.
"So girls, let's find us a boulder!"Twilight peered around several shattered walls. On several occasions they pushed one down, but they were never big enough to do any real damage to the wall below. On the 7th attempt the wall cracked.
"Ah think the weight of all of those boulders is weighing down on the wall."Applejack explained.
"Yeah, must be. So..."Twilight watched the boulders.
"What if we keep hitting it with the same boulder, with magic?"Rarity suggested.
"Rarity, sometimes you are a mastermind."Twilight patted Rarity on the shoulder.

~~~

Twilight hauled the biggest boulder so it was above her head. She threw it at the pile of rocks again and it cracked just a little more.
"Twi...this is taking forever, and lifting these rocks is VERY taxing after a while."Rarity panted.
"I know...but I think we're nearly through."Twilight responded.
"Hey y'all, look out!"Applejack called from the top of the hill above the two Unicorns. A moment later and Applejack and Fluttershy were pushing a large rock made from several smaller rocks tied together with rope.
"Uuuh, Twilight, do you suppose we RUN AWAY!"Rarity suggested, running away from where the rock was going to hit.
"Good idea!"Twilight responded, diving away. The rock fell away and hit the original pile, ripping through the wall.
"My, that worked better than I thought it would."Fluttershy commented as she followed AJ down.
"No time to talk, girls, we have to search the inside for survivors."Twilight stepped inside the ruined Palace, now just a shell of it's former glory.
"AND find that tower!"Rarity followed. As the four stepped inside, they noted several things:
For one, it was remarkably intact and was supported by multiple wooden beams on the inside(one of which they had broken).
Second, the steps going up had been somewhat repaired, enough to use.
Thirdly, occasionally they heard footsteps upstairs.
"Y'all, I think somepony's home."Applejack pointed to the ceiling.
"Survivors?"Fluttershy suggested.
"Looking at the fact no one has broken in before us, I'd say that's about right."Twilight was watching the stairs.
"Um, girls, I think we should block up this hole with something."Rarity suggested.
"Good idea. Then nothing can follow us in."Fluttershy nodded. Twilight 'grabbed' the big boulder AJ and Fluttershy had made and pushed it back, nicely blocking the hole.
"Who's there?"the four heard from the steps. The pony who said it, the tone obviously sounding like a Royal Guard, was just out of view.
"Twilight Sparkle, and three of her friends."Twilight answered.
"Twilight? The Princess has been trying to spot you since Canterlot stopped! Quickly now, come upstairs."the Guard responded, coming further down and motioning the four over. He led them up about three odd floors of depleted guard squads watching the staircases from behind crude barricades. At the top one Celestia was watching Canterlot from a window, trying to spot something.
"Princess Celestia, you can stop. Twilight and her friends have come here."the Guard informed. Celestia turned, and as soon as she spotted her student and her friends she ran over and grabbed Twilight, obviously overjoyed to see her.
"Twilight! Thank the heavens you are alright! Where are your other friends? Rainbowdash and Pinkie Pie?"Celestia asked.
"We don't know. We came here hoping to use this place like a lookout to spot them, namely the tower."Twilight answered.
"You mean the one still standing?"Celestia asked.
"Of course."Twilight answered.
"Well that's the problem..."Celestia scratched her forehead.
"What is?"Applejack asked.
"During the disaster the entrance collapsed. Luna was forced to run up there to escape being crushed. I fear she may be injured, or worse."Celestia answered.
"We need to rescue Luna! We would be in great trouble without her!"Rarity tugged at the debris.
"Right. We need to rescue Luna."Twilight nodded.