Tirek smiled to himself.
Why would't he? He had just finished his plan to enslave Equestria. He had all of the magic of the Unicorns, Pegusi, Earth Ponies, and the Alicorn Princesses. While they almost tripped him up by by putting their magic in a fourth princess he didn't know about (must have just ascended) he was able to gain her magic with a little bit of a hostage situation. He even managed to drain the mighty Discord of his power, fool didn't realize he would be betrayed until it happened. Not that it was his fault, Discord was always going to be drained. The only reason that Tirek tricked Discord into helping him was so that Discord wouldn't interfier until Tirek was powerful enough to drain him, that fact that he was able to accelerate the draining of the rest of Equestria was mearly a bonus.
Tirek's smile grew wider, their was no one left to oppose him now.
"STOP IN THE NAME OF THE LAW!!!"
Tirek's smile faded, almost no one.
Tirek looked to see who had the audacity to oppose him, he was sure he drained all of the ponies. On a nearby hill he saw a rather strange being. He, at least Tirek was pretty sure it was a he, was a tall bipedal creature with the head of a dog and blue fur, his face set in an expression that screamed determination. He was dressed all in black with silver detailing. At his side was a sword with a hilt shaved like a dog's head. However, the strangest thing was that he looked somewhat famillier.
"Well," Tirek thought to himself, "at least I didn't think I had drained all of the pathetic ponies while missing one. Not that it would have mattered," Tirek's smile returned, "or will."
"So," Tirek roared, "do you think you can beat me, little Diamond Dog?" Sure in his victory, Tirek closed his eyes and started laughing.
That was a mistake.
If he didn't laugh, he might have heard the blue stranger mutter "Diamond Dog?" to himself in a rather irate tone. If he had not closed his eyes, he would seen one of the eyebrows on that dog shaped head begin to twitch. But even with all of the noise he was making, even Tirek could hear when he stomped one of his booted feet on the hill, causing the entire thing to give way.
Tirek opened his eyes, and when he saw what was under the hill, he stopped laughing.
Beineth the mass of dirt was an enormous building, easily the size of Canterlot Castle. It was a behemoth of metal and glass a hundred stories tall. At the top, upon which the blue stranger now stood, was a mechanical looking dog's head. Upon the front was a peculiar insignia, a shield with the profile of a dog's head on it.
Tirek's smile disapeared as he remembered where he had seen that embilum before.
The Blue stranger started talking again as he pulled a device out of the pocket of his treanchcoat. "Nobody calls me a Diamond Dog, but I thought you would remember that from the last time I put you away."
From the depths of the Everfree Forest came a series of multicolored beams of light. As one they shot towards Tirek, dissipating to reveal the Mane 6 enfuzed with raw rainbow magic.
Of the 6, Twilight was the first to speak. "Alright Tirek, time to..." She trailed of as she saw the scene before her.
Tirek was there, on the ground, covered with bruises, sobbing like an infant. Standing over him was a giant, metal, thing. It stood on two legs, was garbed in mostly white armor, and covered with flashing lights and energy weapons of some sort. It's head was encased in a helmet reminicent of a dogs head with a yellow visor covering its eyes.
Noticing their arrival, the behemoth turned towards them. As the girls tensed for what seemed like an inevitable and difficult battle, the giant did the last thing any of them expected.
It saluted.
"Princess," a voice from the giant boomed, "good to see you here. Commander Cruger reporting for duty, and requesting assistance in the extraction of the stolen magic from the suspect."
Twilight responded in the only way she could.
"Huh?"