Helpless against Hyperion's relentless onslaught, Periapsis realized that being on the defensive was a losing situation. There was only one way she could save ponykind, and that was to kill Hyperion. She knew he was unbeatable physically. There had to be a way she could outwit him. She knew there had been ancient alicorns who suffered spectacularly fatal burnouts. If she could cause him to burn his horn out somehow, she would be successful.
The last remaining mortal pony city that was still populated was under attack. Periapsis and her daughters rushed to meet the aggressor head on. Hyperion was enjoying himself, taking his time with his victory imminent. Some of his most cruel ways of killing were on full display. He would telekinetically pull their bodies apart or turn them inside-out while forcing them to stay alive during the process.
Peri slammed into him with the speed of a missile, knocking him through several buildings before skidding to a stop against a hill. He laughed and congratulated her for the effort. He then struck back, burying her under tons of falling rubble. The two continued fighting, each inflicting only minor injuries upon the other while the surrounding landscape looked like a hundred bombs had been dropped on it.
Hyperion focused his attention on Celestia and Luna, seeing them vulnerable. He had hoped they would be the cure for Peri's insanity. It was now time to end that mistake. He charged at them, but Peri intercepted his efforts with a shield bubble around the sisters.
A matured alicorn's shield is effectively impenetrable. It was little effort for her to maintain it, and her daughters were safe for now. Hyperion made a show of telekinetically throwing live ponies at their shield with such force that they burst upon impact. The greatest pain was felt by the sisters themselves as they could only watch in horror.
Peri knew it was time to end this. With her daughters protected within the shield, she pounced on Hyperion and held him with all her strength. She then manifested magical chains to bind the two of them together.
With the two alicorns chained to one another, she then focused on his horn, bringing to bear the unfathomable power of the Aether against him. Peri's magical abilities were easily on par with Hyperion's, even if her physical strength was somewhat less. With the intense onslaught against his horn, Hyperion had no choice but to raise a magical defense to protect himself.
He tapped the Aether for the energy necessary to keep his horn from being destroyed. For that was the only real threat here. An alicorn's horn is his life. Fortunately for him, it would take an inconceivable amount of energy to actually destroy his horn. He was only mildly concerned because Peri would need to tap so much energy that she would risk her own life in the effort to end his.
And that was exactly her plan. Periapsis abandoned the hope of self-preservation. The entirety of Hyperion's focus was now on hardening his own horn. He had nothing left even to break the chains and wrestle himself away from her grasp. For the first time in his life, Hyperion experienced fear.
The energy being used by both alicorns was orders of magnitude brighter than the sun. The surrounding buildings were set ablaze. Celestia and Luna watched helplessly from within the shield that protected them. They only hoped the mortals had enough sense to put as much distance between themselves and the alicorns as they could.
Hyperion's horn began to vibrate with the increasing stress. Peri closed her eyes and willfully dropped the final portion of her restraint, tapping the infinite power of the Aether, beyond her horn's ability to withstand.
With a tiny fraction of the energy she was using, Peri brought time itself to a near standstill. She and her daughters appeared in the star-filled void of the Aether for just a few seconds. “Goodbye, my children,” she said, her tone bittersweet. “Take care of them. Rule them well.”
And then she was gone.
Hyperion felt his horn's integrity begin to fail. He had no choice but to tap more energy than he could safely use. Sensing that his defeat was imminent, he likewise slowed time to a near standstill, for only himself. With his remaining milliseconds, he designed the instrument of his vengeance.
His senses reached out to a nearby apartment complex, collapsed from the battle. Within the rubble, a heart was still beating. A mare, heavy with foal, who would have given birth within a month, in better circumstances. Hyperion reached out with dark and potent magic, and snatched the living soul right from the foal’s unborn body.
Into this innocent foal, Hyperion poured his wrath—an irresistible directive intertwined within her very essence. She would become the personification of his hatred and malice. She was now the Nightmare, existing without body or form until the time was right.
She would survive Hyperion’s physical death, lying in wait for somepony to fall into the trap. And when she was finished with ponykind, his vendetta would at last be fulfilled.
Time resumed, and in an instant, the two alicorns experienced a fatal burnout. The unrestrained energy flowing through each of their horns created an explosion that completely leveled the city. A shockwave split the ground, creating a long and deep ravine. Bare rock became molten glass. Everything else had been vaporized, scattering to the wind.
Hyperion's horn shattered into thousands of fragments the size of grains of sand. The force of the explosion dispersed the remnants of his horn for miles in every direction. Peri's horn remained intact, but her body was obliterated, leaving the horn embedded in the molten rock at the bottom of the gash in the earth.
Being severed from her skull, her horn transformed into a dark blue crystal.
The shield protecting the royal sisters collapsed, leaving Celestia and Luna hovering there above the barren landscape in complete shock. Their parents were simply... gone. The alicorns of old were no more.
As much as the old mythological vibe of this story is fun... There's one aspect of it which doesn't make much sense to me. If Hyperion and Peri are these planet-wide uber-powerful beings, teaching their children global-scale deep magics... Why are ponies the only lesser species mentioned? What about the various other species in the MLP world? The griffons, and minotaurs, and zebras, and so on? The only way I'd view the story as making sense is if those species are somehow all introduced later on in history by some force currently not introduced.
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lol... you been reading my notes?
Griffins and minotaurs were indeed artificially introduced into Equus by some force not currently introduced. So you pretty much nailed it, although that force isn't part of this slice of the timeline. There's a broader conflict going on that is visible only by zooming out even further to the more ancient past and then into the future when the saga enters a technological revolution, including space travel.
While all of that isn't part of this story, I might as well state that there's an ongoing interstellar war between two titanic races known as the Alcora and the Windigo. (yes, those Windigo.) The focal point of the conflict is that the force of Harmony, generated by ponies of all three tribes getting along, annihilates windigo. The Alcora discovered this and want to weaponize it to destroy their enemy.
You can read a finished story in the sci-fi future part of the saga by checking out Flurry in Time.
But yeah other mortal races do still exist during the calamity Hyperion brought. But they were not the target of his wrath. His aim wasn't to demolish the world. Just to wipe out the ponies specifically. Collateral damage would have hurt everyone, to varying degrees, but that isn't the focus of this story. It's just mentioned in passing. Next, the story will cover the aftermath and what the sisters did to help rebuild.
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So the part that confuses me is... Why did Hyperion hate ponies specifically, when other intelligent species were doing the exact same thing in terms of building cities and stuff that he would have viewed as blemishing his landscape? By the way, thanks for such a detailed answer.
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Oh he tolerated them building stuff, though he found it somewhat irritating. The crux of the issue is what the early chapters introduce, where Periapsis took a special interest in the ponies.
The reason Hyperion never got upset with the other races is because his mate never spent her time paying attention to them. The mortal ponies were her fascination and she wasn't willing to give that up.
The City Must Survive!
(I have no idea why I suddenly had to think of this. I mean the situation isn't even particular comparable...)