The royal palace shook as Princess Luna and Lord Umbriel unleashed beams of energy from their horns towards each other. In spite of Luna's efforts, Umbriel would not budge. He remained hovering in the air, unfazed as he concentrated his energy against his opponent. Eventually, they were both overcome with fatigue and simultaneously ceased to produce magic from their horn.
"Most...impressive!" panted Princess Luna. "I have not gotten a good fight out of another magic user in such a long time."
"Obviously, you don't fight Changelings that often!" stated Umbriel in response. "At least, not those of royal blood!"
"It does not matter!" said Luna. "I can still defeat you, all the same!"
"Then let's go on and see if you are right!"
Umbriel prepared to blast Luna again with a magical beam, while Princess Luna fired another of her own. The beams collided, then splintered apart. Lord Umbriel beat his wings very quickly, and smashed into Luna's body. But this time, Princess Luna took his weight and pushed him back against a wall. Then she fired a blast of magic at him, causing him to slide to the ground in a crumpled heap. The Changeling groaned, then shook his head. He rolled over, and hovered in the air again.
"But...but...that was supposed to put you in stasis!" said Luna.
"Well, unfortunately for you..." said Umbriel. "I am resistant to such spells."
"How?"
"Royal Changelings are very resistant to such spells. How do you think we were so good at capturing others? Lying and trickery aside, mind you."
"Enough! Obviously, we won't get anywhere by simply using our magical skills!" said Princess Luna.
"Then shall we meet our ends by brute force?" asked Lord Umbriel.
"You're on!"
Princess Luna beat her wings, and tackled Lord Umbriel in mid-air. The two began wrestling throughout the corridor. As they went, they knocked over several statues and decorations in the corridors their fight traveled through. Eventually, Umbriel blasted a hole in the wall and the struggle spilled out into the city. The two grappled each other, and they dropped down to the streets. Umbriel seized Luna by the chest, and turned her around, so that she was looking away from him.
He started to squeeze her ribs, despite Luna's efforts to break free. But Luna's bones were very strong, no doubt an attribute of her earth pony-like strength, and wouldn't break apart. But Luna wasn't strong enough to completely break free of Umbriel's thick hooves. Umbriel intertwined his back legs around Luna's so that all four of her limbs were locked in place. Luna tried to push Umbriel back, but Umbriel countered each attempt with an attempt of his own to ram his pelvis into her lower back. The two grunted and growled together in sequence with their grappling and struggling.
"No need...to struggle, princess." said Umbriel, half-grunting. "Why bother fighting? We...all go through...with this...sooner or later!"
"What do you plan to do now, Umbriel?" asked Luna, breathlessly. "You're out of the palace. Why don't you just leave now?"
"Oh, so you're not concerned for your student's safety?" asked Umbriel. "Did you forget that she and her pathetic gaggle of friends are at the mercy of my soldiers?"
"That may be..." said Luna. "But I have--ah!--confidence in Sunset Shimmer--ugh!--that she will...succeed in her mission. The least I can do is make sure you don't cause any further harm to Equestria! If you will not leave now, then you must pay for your crimes!"
"Oh, stow it." said Umbriel. "Either try fighting me, or I will destroy you."
Luna's horn emitted a bright flash of light that temporarily blinded Umbriel, allowing her to break free. The alicorn and Changeling unleashed another barrage of offensive spells at each other as they flew towards each other. They came up close to each other, pressing their front hooves into each other. Even though Umbriel's legs were considerably thicker and stronger than Luna's, the princess was still able to hold her own against her adversary.
"Impressive." grunted Lord Umbriel. "So those books were accurate, after all. Alicorns do possess the super-strength of an earth pony!"
"Art thou daunted?!"
"Not at all!" said Umbriel. "In case you haven't noticed, I'm very strong, myself! I, Lord Umbriel of the House of Thorax* and the second-in-line to the Changeling throne, am not one to be taken lightly...ever!"
And then the two exchanged several swift blows with each other, but were unable to deal any considerable damage to the other. Eventually, at least forty guards from both shifts had circled the opponents, maintaining a solid perimeter of unicorns and pegasi.
"Give it up now, Umbriel!" said Luna. "There is no hope for you to escape."
"What did I just finish telling you?!" growled Umbriel. "If you are going to insult my skills further, then you leave me no choice!"
He raised his head, and a blast wave knocked all of the guards backwards. In the confusion, Umbriel zipped back through the air, and landed straight in front of a crowd of civilians that had gathered over the last couple minutes.
"One last chance, Umbriel." said Luna. "Surrender now, or die. You are all alone here!"
"I think not!" said the Changeling lord. "You see, one will find that we Changelings are--and forgive me if I am using a borrowed phrase--more than meets the eye."
Just like that, the crowd of ponies behind him became a bright green inferno, and by the time the fires cleared, everypony in that crowd was replaced by a Changeling. And there were many of them, at least fifty or sixty. And standing tall and proudly at their head was--
"Ah, sister!" said Lord Umbriel. "It is good to see you again! But really, this was wholly unnecessary."
"On the contrary, brother..." said Queen Chrysalis, who slowly trotted up to Umbriel. "I do believe that you are embarrassing our empire!"
"Perhaps, perhaps." said Umbriel, who casually strode to join his elder sister. "But if I do remember correctly, you were okay with this!"
"Perhaps at first, but now is the time to pack up your toys and come back home with us." said Chrysalis.
"Really?" asked the younger regent. "For what occasion, may I ask?"
"A Changeling royal summit." said Chrysalis. "Your lap-dog Ghost told me something very interesting."
"Oh, really?" asked Umbriel, before turning to Luna. "Sorry, sweetheart. You and I will have to cut this session short."
"You shall not go anywhere, you vile monstrosity!" snapped Princess Luna.
"Oh, I beg to differ." said Lord Umbriel.
"You wouldn't risk breaking your truce with my empire just yet, princess!" added Queen Chrysalis. "Not without your older sister's consent!"
Princess Celestia flew down from the palace, flanked by a squad of pegasus guards.
"Let them go, sister." she said, reluctantly. "As long as they do not perform any more crimes against Equestria, we have no quarrel with them...for now."
"But sister, Umbriel would be free to harm Sunset Shimmer even further!" said Luna.
"Oh, so that's what all this trouble is about?" asked Chrysalis. "Well, I am going to have a long talk with my brother when we get back to my lair. Come, brother!"
"Yes, sister." Umbriel bowed his head proudly. "Let us leave this place."
Then the two Changeling regents took off into the air, and the drones around them either teleported away, or took off into the sky after their leaders. Once the Changelings all left, Luna turned to face Celestia.
"Sister, what is the meaning of this?" she asked. "Why did you let them all just leave?"
"Because Queen Chrysalis may be the only one able to keep Lord Umbriel in line." said Celestia. "And we do indeed have a truce with the Changelings at this time, and I would not risk breaking it here and now."
"I understand, sister." said Princess Luna. "But still, we must send more guards to help Sunset Shimmer in Vanhoover."
"That, we shall." said Celestia. "And I will take the liberty of sending my own guards, too. After all, Sunset was my student, too."
"Okay, does this look like that cave you two found?" Trixie asked Nose Nip and Frosty.
"Yep, it sure does." said Nose Nip, inspecting the tunnel the four ponies reached.
"So, who goes in first?" asked Pressure Point.
Trixie shot a look at her cousin.
"Hey, don't look at me!" scoffed Pressure Point. "I didn't sign up for something like this!"
"You didn't sign up at all, Pressure." said Trixie. "Now get your Ph.D ridden flank into that cave!"
"Blast it, Trixie! I'm a doctor, not a spelunker! Frosty, why don't you go in first?"
"Sorry, but I'm more into climbing and hiking, not going through deep, dark caves." said Frosty.
"Oh, you're all a bunch of stubborn mules." said Trixie. "If nopony else wants to take point, then I shall do it myself. Now follow me closely, everypony."
Pressure Point, Nose Nip, and Frosty reluctantly followed after her, grumbling about uncomfortably cold the cave was. After twenty seconds, Trixie halted in her tracks.
"Wait, does anyone else hear...buzzing?" she questioned.
Right on cue, several dark shapes sped towards them in the darkness, all beating their insectoid wings.
"Shoot, it's an ambush!" shouted Frosty.
But Trixie Lulamoon and Pressure Point were ready, and shot off several offensive spells from their horns. The winged attackers were quickly incapacitated, except for one.
"I've got this one!" shouted Nose Nip, who galloped forward and tackled the last one.
"Ow, right in the blinkin' head!" yelped the Changeling that Nose Nip subdued. "Why'd they always go for it?!"
"Wait, I recognize that voice!" said Trixie.
"So do I." said Pressure, whose horn glowed and illuminated the tunnel. The three unicorns could now see that Nose Nip had tackled a Changeling that was not only slightly overweight, but sported an underbite.
"That's the one that led the attack on the train!" said Trixie to Pressure Point. "You know, the one with the funny accent!"
"Yeah, lovely to meet ya again, too!" said the dazed Changeling. "Name's Sigma, in case ya forgot."
"Well, at least we can say we're on the right track." commented Frosty.
Sunset Shimmer continued to nuzzle against General Synthe, oblivious to the strange grin he was giving her. He was also beginning to pant heavily.
"Craw, what are you doing?" Sunset asked, dreamily. "What's with that noise?"
"Keep going, Sunset!" Synthe thought. "What you're doing is making me feel...so...good!"
The inside of his body was surging from all the love that Sunset was emitting. It felt positively refreshing to him. He could feel his wounds healing slowly. His scars began to contract and fade. He felt his body stretching here and there. His legs were regrowing, but the plating and prosthetics were obstructing their growth. Quickly and painfully, he ripped them off to reveal his shiny new limbs. His wings regenerated, and extended to their original shape.
Then Sunset realized what was happening, and gasped in shock. Instinctively, she teleported away to the other side of the room. But it was too late: Synthe yanked off his breathing-device and even pulled out the breathing-tube that ran through his jaw. The wounds almost automatically mended themselves.
"What in Equestria?!" exclaimed Sunset. "What's happening?"
"I will tell you what has happened, my dear Sunset Shimmer." said Synthe.
He let out a horrible cry, and a shiny black horn protruded from the broken stump, smothered in greenish blood.
"You have just made me..." said King Craw. "A very, very happy Changeling!"