Princess Celestia paced slowly and gracefully on the marble slabs that tiled her main hall. The exquisite stained-glass windows showered the hallway in multicolored hues, painting the guardponies standing at attention by her throne in chatoyant streaks of light.
When she reached the end of the hall, before it branched out into the great reception chamber, Celestia turned and ambled back toward her throne room again. Back and forth, lost in thought and concern, she had been pacing this way since morning.
"Tia... please join me for midday meal. Thou wilt not come closer to thy goal wearing a rut into the palace floor." Princess Luna was trying to be whimsical in her approach, but the look on her muzzle indicated deeper and more complex concerns than lunch.
"She is out there, sister. Uncontrolled, uncontained. She knows to hide; her purpose cannot be good. Somehow she must be found. If she were here in Equestria the matter would be over; but out there, in the human world, I am blind and forced to wait." Celestia was being her quiet, serious self now; a facet Luna knew all too well.
"A frightened mouse always runs away from the cat; she is only a mouse, Tia. She has not used any power save to flee, if she had, thou wouldst know of it and pounce. Canst thee not consider this mouse to be without guile and driven only by the same wish to live that commands all hearts? Why cannot this new sister be embraced instead?" This was the first time Luna had directly confronted Celestia over the matter; for these ancient beings such questioning was equivalent to an impassioned argument.
"Do you forget the reign of chaos?" Celestia had stopped her pacing and stared directly at her sister; the hue of her timeless eyes was colored by endless years.
"Beloved sister, Tia, this little foal is not Discord. I do not believe she is any kind of threat. Is there no love in thy heart for thine own unfortunate subject? She did not ask for this, I am convinced she doth desire none of it." A potentially dangerous admission; Luna calmed herself so as to betray nothing to her sister.
Celestia studied her sister intently; she felt a hint of more in her sister's words than mere speculation. She turned and faced away, the burning sun on her flank striped with hues from the windows. "When the merest whim, the faintest whisper of thought can reshape the world, innocence is less than a blessing, rather it is the very fount of calamity. Her innocence only compounds that peril which she represents to us."
Celestia turned her head back to look levelly at her sister. "The peril which she represents to us both."
The words were quiet, but the meaning they held was as weighty as the moon itself. Luna understood only too well what was truly being said.
A thousand years in the past, she and her sister Celestia had managed to conquer the great enemy, Discord. History recorded Discord's reign as lasting a thousand years; convenient round numbers were ever the comfort of the court historians. But those aged, arguing scribblers of tomes knew nothing, and understood even less.
Under Discord's reign, mountains could become pudding, and entire landscapes turn to twisting ribbons of silken lace within the time of one breath and another. Nothing was stable; nothing lasted. Space was a dream wrapped in candy and distance a gravy-flavored snake that writhed back upon itself. Nothing material could be trusted, what was in one instant a simple home and bed could in another moment be a lake of liquid fire hanging in the sky or a living, thinking beast made of spaghetti and doorhandles. Neither life, nor soul, nor substance, nor meaning itself could last for long; reality itself was constantly in flux and nothing ever remained unchanged.
In such an insane cosmos, there could be no rational accounting of time. To say that the reign of Discord lasted a thousand years, or a quadrillion, or a mere second would all be truth; the ultimate horror of constant change had forever scarred both Celestia and Luna; they had suffered under Discord effectively forever and ever and never. Luna often thought that Discord actually wanted to be conquered, that even the tyrant of chaos was tired of his rule. He had certainly permitted his defeat to happen.
In chaos all things must exist, given enough time. Even order must occasionally spring from randomness; chaos contains all things as a subset of itself. Disorder inevitably births its own demise, because it must; in chaos is all possibility, and one such possibility is its own end.
The pony sisters had fragmented memories of something like a life, but they knew all of it may not have been real. There was no valid proof that they had ever lived before the moment they both found themselves aware. Celestia and Luna had often considered the possibility that Discord had simply brought them into being, with a fragmented memory of a fictional past to soften the blow of their sudden creation; but there was no way to know for certain.
They had a vague and broken conception of having been sisters, of having lived as some kind of royalty within a castle; but neither of them could concretely recall parents or their own childhoods. The castle had always been ruins; surely it must have once been complete; then again, perhaps it too had no actual past. They haunted it, though, for in the constantly changing world, the slowly shifting ruins offered something almost like stability. This was doubtless another game for Discord; the broken castle was a toybox into which they were permitted a meager island of relative persistence.
That he favored them as toys was clear; what they endured under his whim was beyond even any ability to comprehend entirely. That they found the elements of harmony was suspicious; but then such artifacts were themselves random possibilities too, and given enough time, inevitable outcomes of Discord's ever-rolling dice.
The sisters had suffered many forms and many shapes, but their opportunity came when, for the sake of chaos, they had found themselves alicorns, growing in godly, supernal power with every passing second. Though driven essentially insane, they still had somehow together found a thread of mutual purpose, and between their own new divinity, and the elements of harmony, just enough power and reason to bind and seal the tyrant Discord.
But even after Discord's defeat, the sisters struggled to refine and accumulate their sanity; to stabilize both the still-churning world and their own minds and hearts. A thousand years of chaos - a meaningless phrase, uttered by ignorant authors of empty histories.
For a literally indeterminate time, Celestia and Luna fought their every whim, every thought inside them; the merest daydream could reshape the land or dissolve the sky. Eventually they found a peace inside, born of constant control and vigilance, enough to keep the land below and the sky above, enough to permit light and shadow, enough to grace a world with life that remained and grew and finally thrived.
It took an iron will to settle themselves and thus the world into order, to keep reality itself constant and stable. Celestia, with her grim, determined mind was the undisputed champion of this terrible discipline, and she not only kept reality intact, she became the anchor for Luna, who struggled to remain balanced in time and space and meaning.
At least until that day, that night, Luna could no longer keep her own inner peace, and lost herself to her own anger and misguided passions.
Her time imprisoned as an aspect of her own moon had saved the cosmos. If Celestia had not imprisoned her, Luna knew how easily she could have dismantled reality itself, and how rapidly chaos would have again swallowed them all. A mere thought, a mere whim; this was the horror that such absolute power represented. They could not know everything, but they could do anything, and nothing could be more dangerous or terrible than that.
The generation of a new alicorn was a known possibility. The deepest secret of Equestria was that magic, despite the endless study of the unicorns, could never entirely be reduced to reason and logic. It was born of chaos, of the same mother that had spawned Discord, and patches of chaos still scarred the land of Equestia; the Everfree forest was such a scar; a permanent wound that reality itself had suffered during the original battle to defeat Discord.
The cosmos of the humans was, like the Everfree, a realm of chaos; though seemingly orderly at first glance, it was founded on uncertainty and randomness at the finest level, and had originally sprung forth from that foundation. Thus it was an understood possibility that an alicorn might potentially be created. Even one was too much.
Luna understood the threat such a being represented as well as her sister; but she also held pity for such a being. She herself would not exist save for the pity of her sister; Celestia had allowed lessers to use the elements of harmony, knowing that in their hooves, Luna would not be destroyed, but only stripped temporarily of her deific power. Long enough for a second chance, long enough to feel what being vulnerable and helpless meant once again. Long enough to rediscover sanity once more.
Lillian had not tried to use her powers; Luna had seen this. The infant alicorn had diligently avoided their use, and chosen to simply hide. Another pony might have tossed the binding ring away and opened wide the fountains of creation; within hours a concerted will to power would have inevitably made such an ambitious creature no longer flesh. They would have been permanently transformed into a threat as dire and eternal as Discord himself, and thus become the ruination of two universes.
Yet Lillian had not done this. Celestia had good reason for her harsh intentions, but she was consumed by her arguably well justified fear. Surely, properly bound and nurtured, there was another path that could be trod with regard to the new alicorn. If only Lillian had not been created from humanity, Celestia might listen. But humanity was dangerous and self-destructive, and that was the only vision that Celestia now seemed to have of their kind. It was not her fault; humans had more than a little of the flatulent spirit of Discord within them, Luna could smell it; and the odor was intensely strong.
But Luna, if anypony, had pity for the lost, the abandoned, the disregarded. She saw in the new sister a reflection of herself, when she had been lost to everything.
"Tia... Celestia, my dear and beloved sister, I would ask of thee something most heartfelt; please consider the pity thou didst show to me, and the love thou hast found returned in kind. I beg thee to find such pity again, should thy path finally cross with that of our terrified, infant sister." It was all Luna could do, for now. Plant a seed of compassion in the hope that it would bear fruit in time.
Celestia turned fully to face Luna; her expression softened by a deep knowledge of precisely why her sister would be so strongly moved. "Lulu, dear one, you know that I..." Suddenly Celestia stopped, her face lost in concentration. Her ears panned the room, she tilted her head as if listening. 'Northern' hemisphere of the strange, spherical, human world. Middle of the region they called the Northamerizone. Celestia's vast consciousness focused in; she could envision the flat plains interrupted by a human city; going closer still, she found a single building, and within it...
"There!" She said with quiet excitement. "Gotcha."
And with that, the room filled with blinding light, as Celestia vanished into the strange places beyond normal space, to run through the secret passages behind the curtain of reality itself.
Alone, save for the curious guards by the throne, Luna understood what happened; Lillian must have removed her binding ring, and become visible to Celestia again; Luna herself could feel the presence of the newfoal alicorn, like a tiny candle seen at the edge of vision in a vast, dark room. She could also perceive the bright glare of her sister racing to meet that candle.
No. Celestia was caught up in her chase, in her concern for the welfare of every living being, and certainly the danger was real and the threat was dire, but Luna could not accept that there was only one safe outcome. Celestia had taught her friendship and love; her older sister only needed to be reminded of the full scope of her own lessons.
That was something a truly loving little sister was honor-bound to do.