Humanity was a master of warfare - a race does not simply spend its entire life in conflict and not become a master of it. Humans had the art of war down to a science - they knew when a fight was a sure thing, and when it was going to be a washout, even when it didn’t seem like it.

And recent events had tried their resolve sorely. Even now, most of the world lay a desolate ruin, devoid of human life, rendered uninhabitable by thaumic radiation, and  much of humanity absorbed by the island in the ocean thanks to the Conversion Bureau Initiative. What remained was small, some would say pitiful, an enclave of humans who refused to believe that this was where humanity came to an end. Even as the waves of thaumic radiation washed uncontrollably over the earth, taking more and more territory from them, they stood firm, and kept working on inside their little fortress of humanity.

One day, their perseverance was rewarded. Scientists clapped and soldiers cheered as the first ever magic-proof alloy was produced, deflecting the spell of a captive unicorn. The foundries roared into life, and the sky grew black over the fortress with smoke, as the remnants of humanity dug out old plans for global scale warfare, and put every ounce of their species’ creativity and power into forging the machines that would level the playing field.

And scarce half a year after that, the fruits of their labor were unleashed, just as a storm of thaumic radiation rampaged through their home for good. None died, the last humans alive having boarded their finest creation, the greatest machine ever built by man.

Four legs the size of skyscrapers. A central, roughly spherical torso that was home to the biggest fusion reactors humanity could build, and the utilities required to support a crew of fifty thousand men and women.

The 4L-GWM “Tyrant” - the first and last war machine of it’s kind, with the kind of destructive capacity that could set off alarm bells around the world, no matter who was driving it. In times past, it would have been nuked from orbit without a second thought by Palladion, the global security AI.

The difference now, was that Palladion itself was occupying the machine, the only AI capable of coordinating such a complex machine, down to opening individual doors at spoken request. The only one trusted to carry the fate of humanity in his digital, iron grip.

Oceans did not slow the machine, and the Tyrant stepped into the ocean as casually as a child steps into a paddling pool. Waves surged against the purple-tinted, steel-grey armor plating as it began to wade off the edge of the eastern seaboard, and stamp towards the glittering dome in the middle of the ocean that was Equestria.

It was a machine that was so unsubtle and impossibly huge, any faction in its crosshairs would see it coming long before it even got within the machine’s considerable range.

Celestia and Luna stood at the top of their tower in Canterlot, and could see it on the horizon, past the glittering dome that encompassed their dimension, like some sort of hazy monster.

“By the moon,” Luna gasped. “What is that?”

“I do not know,” Celestia whispered, before squaring her shoulders. “Clockwork Spring!”

There was a quiet click of gears, and a teal unicorn appeared from thin air, wreathed in smoke, bending one knee to his ruler and deity. His clothing marked him as an ex-human, one of the few who insisted on wearing clothes even now. The fact that it was a nondescript, tidy black suit suggested he wasn’t new to the realm of espionage.

“You called, Princess?” Clockwork Spring asked, smoothly.

“Please tell me you know what that is,” Celestia asked, pointing at the lumbering machine far away on the horizon.

“We... do not,” admitted Clockwork. “We’ve marked it’s progress and tailed it as it marched across America, but beyond that, we don’t know much about it. It has not performed any test firing of it’s weapons, none of our agents have gotten into the interior, no crew have set foot outside the vehicle thanks to the omnipresent thaumic radiation, and even the material it is made of is unknown to us, and considerably resistant to magic. All we know for certain is that it is big, was built seemingly with the express purpose of being a surprise to us, and that it is crewed by the last of the humans.”

“Truly?” Luna asked, surprised. “What about the rest of the world?”

Clockwork shook his head sadly. “Apologies. The enclaves in New Zealand, Switzerland and underneath the Pacific Ocean have been subsumed by fatal levels of thaumic radiation since my last report.” Clockwork looked sad. “Astronomy also reports that the moon colony appears to have undergone some sort of violent decompression and detonation, and the last radio signals received were filled with the sound of... maracas. And bike horns. Suffice to say, we’re fairly certain they are all deceased.”

“The last of the humans,” Celestia murmured. “They march as if prepared for war. And yet, I can do nothing about them but wait until they are in range to be hailed. I do not like this.”

“Nor I,” Luna stated. “Forgive me if I seem like a warmonger, sister, but I shall make our guard ready.”

“I will not fault you,” Celestia replied, not taking her eyes off the behemoth machine marching on her country. “Better to be prepared and not need them, rather than be slaughtered like cattle.”

“With your permission,” Clockwork said, bowing. “I will ask Ambassador Sanguinello to send what troops he can from the Gryphon Kingdoms, and send envoys to the Changeling Empire regarding a possible alliance.”

“The Changelings?” Celestia hissed. “They are no friends of Equestria, or did you miss the part where they tried to take Equestria for their own?”

“I am aware,” Clockwork said, not raising from his bow. “But if this is what I fear it will be, we will be facing all that the human race has accomplished in the art of war - an art that Equestria is ill versed in, and will need every ally we can gather.”

Luna nodded. “Very well, you have our permission and blessing. Whoever bargains with the Changelings for their allegiance has the power to strike whatever bargain it takes to get them on our side.”

“As you wish,” Clockwork said. With a second, muted click, he faded into smoke and vanished.