There are five.
Five that are constant. The only five that are constant. Whatever the scenario, in whatever universe, these five will appear.
The Doctor had encountered two since he became the Doctor. He didn't know it but he had already seen two.
And by the time he came home from Minos, he would see one more.
"There we are then!" The Doctor said brightly. "We've materialized! And thank Celestia, it was a bit choppy there for a moment..."
'A bit choppy' was an understatement. Scootaloo was gripping onto the console for dear life, Sweetie Belle had been thrown to the ground from the shaking, and the two Apple sisters were holding each other as tightly as they could.
"Oh there's no need to make a fuss," the Doctor said dismissively. "We're here now, aren't we?"
"Where exactly is 'here', anyway?" Scootaloo asked, composing herself.
"Minos!" the Doctor said excitedly. "Year... Oh, we've jumped ahead four thousand years! Not bad for the old girl is it?"
"We're four thousand years in the future?!" Sweetie Belle squeaked happily.
"Oh, that's nothing," the Doctor smiled. "I told you before the TARDIS can go anywhere at anytime!"
"Yeah, hopefully you don't lose your lunch along the way," Applejack grumbled.
"Let's go again! Let's go again!" Apple Bloom chanted deliriously.
"Not yet! We've landed! There's lots to do!" The Doctor marched to the TARDIS door.
"What, exactly?" Applejack asked.
"What, 'what'? What are you whating about now?" the Doctor asked slightly irritated.
"What is there to do?" Applejack asked.
"Well..." the Doctor thought for a moment. "Stuff.... I don't know! We'll find out when we get out of the TARDIS wont we? We'll never have anything to do with you standing about asking questions will we? Now, come on."
The Doctor stepped out of the TARDIS and the Cutie Mark Crusaders followed shortly behind him. Applejack rolled her eyes and followed them out.
"Welcome to Labyrinth! Capital city of Minos, home of the Minotaur!" The Doctor said grandly. Then he looked at his surroundings and blinked several times. "Though... I suppose you don't need me to tell you that do you?"
Flags. Flags everywhere. In windows, off buildings, on the street. Posters. Posters that said things like 'Onward to victory!', 'Help our boys!', 'Sign up to fight!', 'Daedalus fights for Minos, so can you!', and 'We'll finish what they began!'. There was a general commotion in the street. Minotaur were flocking to one end of town.
"This..." the Doctor took a look around him and blinked some more. "This is a bit much isn't it? I'm all for patriotism, fine, but this is taking it a bit far..."
"Maybe it's some kind of holiday?" Sweetie Belle guessed. "Some kind of Minotaur Independence Day?"
"No..." the Doctor squinted. "Look at the flags. Some of them have been up there for at lest a year. Maybe more? No, if I had to take a guess, I'd say..."
"It's wartime," Applejack finished for him. "This is wartime. Look at the posters. These are recruitment ads."
"That's right," the Doctor said in singsong voice.
"We're in the middle of a war?!" Sweetie Belle frantically searched for something to hide under.
"No," the Doctor said dismissively. "This is the good part! The home front! All civic duty and support our troops and for princess and country all that good stuff. It's spirit! That's one of the very few good things about war. It brings out the worst in some people but for some it brings out the best."
"The Doctor's right," Applejack leaned in close to Sweetie Belle and snuggled her cheek. "We're perfectly safe here, Sugarcube."
"Oh, I didn't say that..." the Doctor pondered.
"What?" Applejack said, suddenly concerned. "But you said..."
"I said that this is the home front in a war," the Doctor said cautiously. "The question is, who are the Minotaur at war with? Ponies may not be a welcome sight in the middle of a Minotaur city right now..."
"The Minotaur have always been friends with Ponies though," Apple Bloom said nervously.
"Well, you have to remember that was four thousand years ago," the Doctor said. "A lot can change in that amount of time."
"Great," Scootaloo muttered. "So at any minute we could be arrested for spying. How do we find out if we're safe?"
"The way we find out anything else!" the Doctor said cheerfully. "We ask!"
The Doctor approached two older Minotaur women walking with the rest of the crowd to the center of town. "Excuse me, Ladies?" The two Minotaur turned to him. "I'm sorry, I've only just arrived. What's all the commotion? Where's everyone going?"
"Oh we're heading to the expo!" the first Minotaur smiled. "Mister Daedalus says he has a new weapon. It's going to win us the war!"
"Yeah, about the war..." the Doctor started. "Who's it with, then?"
The two women seemed surprised by the question. "Honey," said the second, "no offense, but are you stupid or something?"
The Doctor clicked his tongue and winked. "Thick as a plank, that's me!"
"Well," the first Minotaur stuck her nose up a little higher. "I just hope that the rest of our allies aren't as ill informed."
"Oh, we're allies are we?" the Doctor asked cheerfully. "That's good!"
"Our fight's with those awful Changelings," the first Minotaur went on. "You just come to the expo, dearie. You'll get yourself a good education."
"You've got it." the Doctor smiled and walked back to his companions. "Alright, you four. Come with me."
"I'm guessin' we ain't under arrest?" Applejack asked.
"No," the Doctor said. "It appears that Minos is at war with Hive..."
"The Changelin's?" Apple Bloom said. "Aw, they're always startin' trouble."
"Don't jump to conclusions!" the Doctor scolded. "We don't know if they started the war, do we? For all we know the king of Minos could've gone completely barmy and started a mass bloody campaign of conquest. That's why we're going to the expo, to get the full story."
"Expo?" Sweetie Belle asked.
"I'm not sure," the Doctor said cheerfully. "Let's find out!"
The technology on display in the city square was impressive to say the very least.
Even for the time they were in, the Doctor recognized it as highly advanced. Medical nanobots. Food synthesizers. Holographic entertainment. All of these things bore the same brand as was being projected on the screen in the middle of the crowd.
DAEDALUS TECHNOLOGIES
Horns pointed toward tomorrow.
The Doctor, Applejack, and the Crusaders took their place in the crowd. After a while we got the projected image of a Minotaur. He wore a white suit over his black fur, which was in stark contrast to his grey horns. He had a face that looked like it had seen hardship.
"Hello," the Minotaur started. "I'm Obsidian Daedalus, and I have a question for you. Do you remember what happened that cold winter night?"
The footage on the screen switched to that of a military base wreathed in flame. "A few visitors from Hive, and we lost hundreds of our innocent fighting men, and their families that lived on base. That day I, along with you, watched the sky burn. And I, too, vowed to fight."
It cut back to Daedalus. "I am too old to enlist now, but I want to help in any way I can. Which is why I have provided Minos's military with the most efficient weapons I could make. But I haven't done enough. The war has been hard, and victory is far from a certainty. Until today..."
Then the footage shifted.
It cut to three figures in silhouette. Each a uniform height. Each a uniform build. Each a uniform shape.
A shape the Doctor recognized.
"No..." the Doctor was stunned. "No, it can't be... Not here... How? How could this have happened in three separate universes, and I'm involved in all three? The odds are astronomical!"
"What're you talkin' about?" Applejack asked.
"I've seen them before," the Doctor's eyes were contracted in panic. "I know what these are!"
"How could you?" Sweetie Belle was confused. "We just got here!"
"We're in trouble," the Doctor was speaking very sharply now. "Everyone in this city is in danger..."
"What?" Apple Bloom was starting to get scared too. "Doctor, what are they?"
The lights came on, revealing the Doctor's worst fears.
"Behold the Cybermen," Daedalus narrated. "Behold our victory!"