When a “person” was sent through the portal by Juniper, it was always with the clothing they were wearing, and nothing else. They theorized a connection between how this portal worked and how the portal to Equestria worked, but as long as they did not have access to either, it could only remain a theory.
Still, the clothing was useful. Unlike the human bodies they were on, they could be cut, broken down, and put together. And without it, the Void would be nothing but a mountain of bodies stacked as high as a skyscraper.
With it, they could at least give some internal structure to the mountain. A single thread, spliced together out of countless strands, snaking through the entire pile, wrapping around at least one limb of at least every body. A way to keep track of all of the countless souls under their charge.
And on the top layer, with enough layers of jackets and skirts and jeans and dresses, Starlight and Sunset could spend their endless awakening on a “floor” of fabric that let them, at times, forget the innumerable bodies in the layers beneath them.
And when they were alone, they just had each other, and the Void.
And like she had innumerable times before, Sunset nestled her head in the cavernous crook of Starlight’s neck, her crimson hair soft against Starlight’s rough blend of heliotrope skin and coat.
And Starlight did not know why this moment was the moment, and not any of the innumerable moments and eternities they had been alone with each other since the very last bit of the great work was accomplished. But in every previous moment like this, she kept telling herself that there was no hurry, after all, in the face of an eternity to come of moments exactly like this. And she kept putting it off.
Until she didn’t.
“Sunset. I have to admit something to you.”
And that got Sunset’s interest, as the most interesting thing that Starlight had said in years.
“What is it?”
Starlight took in a deep breath that she did not need, and exhaled it, before continuing.
“I was lying all those times before, when I said that unicorn minds like ours couldn’t be sent to the dreamlands like human ones could. Really, there is no difference between them at all, and I could have sent you to be with your friends any time.“
Sunset gave Starlight’s hoof-hand a loving squeeze.
“I know, Starlight. I knew that from the beginning. And I meant everything I said before. That wouldn’t have changed a single thing about me being here with you.”
She smiled gently at her.
But Starlight didn’t smile back.
“No, Sunset.”
No going back now.
“I’m telling you this because that is what I’m going to do.”
It took a moment for Sunset to process this, but the quiver in her voice meant that she truly understood the weight of it.
“What are you talking about, Starlight?”
“Sunset. It makes no sense for both of us to be stuck out here, in an eternity of unchanging nothingness. How can I keep you here, away from your friends, away from the life you deserve?”
"What are you talking about Starlight? The life I deserve? Starlight, you're my life! My everything!”
“I know! That’s the problem, Sunset! I don’t want to be your everything. I don’t want to condemn you to this eternity with me. I love you too much to not do this.”
“To not do what? To make me forget us, and everything we’ve been through together?” Sunset gripped Starlight’s foreleg-arms tight, as if that would stop her from this train of thought. “To make me lose the most precious thing I’ve ever had? It doesn’t matter that I won’t even—” Sunset’s voice was broken, despairing at the very thought of it. “That I won’t even remember it after.”
Starlight smiled serenely.
“Don’t worry about that, Sunset. I learned my lesson. You will remember me, and our love, and all the moments we shared together. As much as I can fit with the story that I wrote for you.” Tears welled up in Starlight’s eyes. “Including why I’m not there with you.”
Sunset gripped her harder. Her knuckles would have been white.
“Starlight! I don’t want to go! I don’t want to leave you behind!”
“I know, Sunset.” Her serene smile flashed into a grimace for just a second. “That’s why I’m not giving you a choice.”
Shimmering blue energies began manifesting in the space between them, reflected in Sunset’s widened eyes.
“Isn’t this the first lesson you ever learned? You can’t just make decisions like this for other people!”
“I did, Sunset. I learned that lesson so well. Just let me unlearn it. Just this once, and I will never do anything bad ever again. I don’t even have to promise.”
The energies coalesced into glistening knives of blue light. The desperation grew in Sunset’s voice.
“But Starlight… I love you so much…”
“I know, Sunset. I know that better than anyone ever could.”
“I could never be happy without you…”
Starlight did not say anything to that.
The knives of blue light began pressing into Sunset’s mind, already beginning to cleave away the memories that conflicted with the story that Starlight had planned for her. Starlight knew every memory and feeling that Sunset had ever had, so it was a very easy task. It didn’t matter that she could feel Sunset desperately trying to access those very same memories, as if holding onto them tight in her mind would allow her to keep them.
In the smallest voice possible, Sunset whispered,
“Starlight… I don’t want you to be alone…”
The knives stopped their movements. In a voice just as small, Starlight replied,
“And what if I do?”
A quivering moment of silence passed between them, before Starlight began to press the knives deeper. But this time, there was no more resistance. Even Sunset’s grip on her relaxed.
Instead, Sunset just stared deeply into Starlight’s eyes with love, just like she had done countless times before. Like countless times before, those bright blue irises sent Starlight’s heart aflutter, and flooded her soul with a peace that she would otherwise never know.
“Could you give me one last kiss before I go? Even if I won’t remember it?”
It took everything in Starlight to whisper the very last thing she would ever tell her.
“Thank you.”
And fittingly, the last stroke of the blade of memory magic that Starlight would ever perform was by far the most artistic of them all.
Cutting away the memory of a last kiss, as it was happening.