“Luna!”
In a flash of amethyst light, Twilight teleported to where her friend lay. She could feel something pull apart within her, some of Luna’s work giving way under the strain of even this small effort.
The thick smoke was quickly cleared by the growing winds, revealing the ruin of an alicorn’s form. Smoke continued to rise in plumes from her, and the stench of burnt flesh was overpowering. What few feathers remained on Luna’s wings were burned black, and much of her body was charred. All over her, what looked like tiny, hair-like projections protruded from the remaining tissue. Yet, even as Twilight felt herself grow cold in dread, she heard a slow, rattling breath from the burned remains.
As Sunset stared in disbelief, Twilight tried to take Luna’s pulse, see if she could be moved. A small portion of charred red flesh sloughed off in her hoof. Twilight stared up at Sunset, eyes full of pain.
“What is wrong with you?!” she demanded. “She was trying to help you!”
But Sunset kept staring at the fallen princess. “She’s alive? But… that… that can’t be what I meant. Was it? I… No.”
She shook her head, eyes closed. “No, of course not. I’ve… I’ve put such weakness behind me.”
Luna managed to open her eyes, forcing herself to focus on her foe despite the pain.
“To cherish life is no weakness,” she rasped. “See how thy heart betrays thy true nature. Stop trying to destroy thyself.”
Luna took in another painful breath. Then, imploring, she cried, “Give up this mad quest, Sunset Shimmer! Lest thou break thy soul upon it.”
“Shut up!” Sunset’s breaths were coming faster now, as she mustered herself for the killing blow. “Okay. I can do this.”
“Sunset, no!” Twilight shouted up at her, covering her friend’s body with her wings. “You know this is wrong! Just stop this!”
But Sunset squeezed her eyes shut, her teeth locked together. “It’ll be easy,” she said again. “I can do this. It’ll be easy.”
Her eyes opened again, sockets overflowing with crimson fire.
“I’ll just pretend you’re Celestia.”
Eyes ablaze, Sunset Shimmer drew again upon the power of her domain. The section of stone she stood upon thrust further up and out from its cliff face like an obelisk. In the stone floor below, cracks began to form. The wind howled louder as a sudden storm gathered, its lightning illuminating her hatred. Sunset Shimmer looked down upon her prey like an equine Chernabog, ready at last to cast them down into fire.
Beneath that glare and the fate it promised, Twilight flinched away, holding and covering Luna as best she could.
Yet, despite injuries that would have killed any normal pony several times over, Luna called upon what strength she had left. She calmly turned herself and Twilight both so that Luna was between her friend and Sunset, putting her back to the impending attack.
Twilight whimpered a quiet, “No.” But she was too weak to fight. And Luna, even so gravely injured, was simply too strong.
Twilight looked up at Luna, and saw her eyes were calm, serene. And, somehow, Twilight was comforted. Then, both of them closed their eyes and held one another. Luna opened what remained of her wings to shield her friend from death as best she could, even as she accepted her own death as the price for her failure.
Then Sunset’s horn unfurled a cone of indescribable, writhing power. Even with their eyes closed, the ruby-gold blast was blinding. A continual barrage of mystical power, fusing the ground to glass as Sunset poured her power into the deaths she had ordained.
For a few seconds, it encountered a shield, and the torrent of magic sprayed to either side of it. Then, Sunset channeled more power, and her attack shattered it like glass. And still, she would not relent.
On, and on.
A shape remained within that epicenter of destruction, a shape that must not be. Drawing upon Phaedra’s living energy, Sunset poured more of her might into the continual beam of destruction.
More power. More. More. More.
The shape was unrelenting, yet not unaffected. It caught the full brunt of Sunset’s mystic fire, absorbed it, glowing with the sheer destructive might that was being poured into it. Stone outcroppings to either side of it glowed, cracked, and were blasted away into fragments. But the shape remained.
“Die,” snarled Sunset Shimmer. “Die… die…die…”
In time, the shape grew even brighter than the flames which assailed it. From above, it was like staring at the corona of a star, or into the heart of a sun.
And even as that thought occurred to Sunset, she stopped her assault, and stared. In wonder. Even in awe.
And perhaps, just a little bit, in fear.
The shape that stood before her was a sphinxlike aura of white heat, shrinking gradually down towards something roughly pony-sized, the blaze of its light receding as it slowly cooled. It became an Isis, a goddess with wings splayed, an ancient being of power and majesty.
Then, features began to be seen.
No longer was this the Lady of Light. Gone was the gentle Guide of the Illuminating Day. For the sake of those she loved, she had set the peaceable scholar aside, reluctantly calling upon her ancient power. It was she who had come between Sunset and her prey. And it was she who had refused to fall.
Again, ancient names rose up in Sunset’s mind, only half-believed when she had read of them as a child.
Shadow’s Bane. Many-Colored Ravager. Blinding Light. The Lady Who Burns.
The figure’s chest still glowed white hot, like metal left in a furnace. Her eyes were calm. To either side of her, glassified stone crackled as it cooled, giving a dull red glow. It was obvious that the assault had weakened her. Yet, behind her, Luna and Twilight still lived, holding one another in her shadow.
Unflinching, Celestia stared upwards at her former student and spoke a single word.
“No.”
And, in the skies above them all, the clouds began to part.