Luna entered her sister's personal study. She found her fellow alicorn, standing by an ornate desk, making a serie of quills float around, signing off forms at a speed that quickly melted down what would otherwise be an unsurmountable mountain of paperwork to mortals like snow under the full might of her sister's sun during summer. The study was rather better protected than during the old days, two millenia ago. Even now, Luna felt the complex array of wards as she walked in and from the thickness of the door and the surprisingly loud slam it did when she closed it, she knew that it was anything but a normal door. And this was rather perplexing. What was so important with the princess's study that it was protected almost as much as the underground vaults?
Hearing her sister enter, Celestia stopped what she was doing and then, put down each of the quills before stepping out of behind her desk. The taller alicorn stared at the smaller one and for a moment, Luna thought she saw something crack with her fellow alicon's expression. For a moment, neither spoke and then, when it seemed that the sun goddess was about to speak, Luna took the initiative.
"I guess that thou has invited us here to address our issue with the strange flow of magic, am I not correct?"
"It is difficult to hide anything from one of the two alicorn sisters, princess. This situation is an extremely strange one, one for which I had not planned. None of my contingencies, even the craziest ones, were designed to deal with one such as this one. I guess..." the white alicorn seemed to hesitate for a moment. "There is nothing to do but to bring you to speed. However, I ask you that you not share any of what I will discuss here with my little ponies."
Luna thought of asking her sister what she was talking about but frankly, she was very confused. Not by what she was saying but... in general. Her awakening had been a strange one and when she had spoken in private with her of her memory problems, she had requested that they discuss this in her study. There was something strange, something about both herself and her sister. And both of then knew it.
"I do not know how it is possible but the fragments of memories you experienced must have been the lifetimes of the members of the Luna bloodline. The Elements of Harmony must have linked them to you and I guess it must be why you were reborn when Nightmare Moon was destroyed."
Reborn, not freed. Luna noticed the wording she used now that none of the little ponies were around. "Do thou means... that the blast of magic we felt in our back, the last clear memory we had before the moment of our return was... us dying?"
"Yes. Murdered and then, replaced by an usurper. What do you remember of the fragments?"
Though the confirmation filled the alicorn with anger, the question brought the fragments into question. They were strange, alien, incomplete. Feelings of ellation, fear, sudden flashes of situations, still images of moments without context. Almost like someone else's memories... and yet, she felt as though they were still hers. And it reminded her of the moon and what she had felt. She had felt... consumed by anger. Literally consumed by anger. Even her brief awakening as Nightmare Moon seemed so... confused. Like she hadn't been truly there until the Elements of Harmony had purified her.
"The Elements of Harmony, one cannot usurp them. We know that changelings can imitate shapes, steal love, become empowered by it but none can steal the Elements. Only through total selfless love as only us alicorns can, can one use the Elements. Effectively, we are the Elements as the Elements are us."
"They understood and they changed."
Luna stared at the taller alicorn, that last statement sinking in. She saw her sister, so strange from two millenia of experience without her, step closer... and then, close her eyes.
"There is a difference between parasiting love and truly feeling it. The usurpers were not ready for what success would truly bring them. They did not understand that the true purpose of the alicorns was to love, not to rule. Discord knew, it was why he struck after the usurpers made their coup. With no understanding of what love truly was, they could not use the Elements of Harmony, for indeed, the Elements are the alicorns and the alicorns are the Elements."
And at this moment, Luna understood. She had always knew of the possibility but if what her sister was saying... "Self-sacrifice. To give everything. To take love into oneself. To channel the love of everypony and become their voice... the usurpers, they did this."
Celestia nodded. "They gave up their dreams of power to become parts of a greater whole, for each member of the usurpers to give up their personal ambition to recreate and keep alive the concept of the alicorns. To become the voice of their love. It was... my ancestor's decision. One I chose to uphold."
And at this moment, before a shocked Luna's eyes, an aura of green flames flashed and the shape of her sister changed. Her horn became longer, jagged, her eyes slitted, fangs poking out of her mouth. The white coat became pure, snow white chitin. The feathered wings became insect-like though retaining a feather motif. Small holes were visible in each leg, near the hooves. Luna was taken aback as the being that had been her sister a second ago looked so similar to a changeling.
She saw her kneel before her, bowing her head all the way to the floor... "In your absence, we have tried to uphold your legacy and to atone for our ancestor's sin. But I realize... that I, like my predecessors, are only fakes. I am sorry, princess Luna, I am sorry for taking your little ponies away, for lying to you. I am unworthy..."
Anger, rage even was tempting, so tempting. A being who was by all means a changeling stood by her, its shape a mockery of the one she had loved. The realization that usurpers had destroyed her body, stolen her life, and effectively even now continued to steal her sister's life...
However, in the rage of Nightmare Moon, even as the six ponies had unleashed their power, the Elements of Harmony had touched her soul, reached out to her heart. She had felt the gentle touch of her sister, of her love. Even if she had suspected that something was off with her sister, her love had been ever so genuine. Though changelings could imitate and mimic many things, love could not be faked.
She walked around the strange one. Even though the alicorn was physically smaller, Celestia XXIII felt like an ant next to a giant. Unknown to her, Luna could see it. Her body was trembling from a fear that couldn't be faked.
"Thou fought Nightmare Moon. Thou stood before the wrath of a goddess, despite knowing thou were not a match for her..." She whispered, slowly looking over her body. And then, her eyes set upon her flanks and more exactly, the sun mark. The disguise was gone but the cutie mark... it was still there. "Thou love them. Thou love our little ponies as if they were yours. Thou were ready to give thy life for them..."
She brushed a hoof against the marked chitin. The magic flowing through did not lie. "Thou haslt bathed in the magic of friendship, accepted it in thy heart. Thou hasth abandonned thy name to claim that of thy sister and become her, to give a voice to the love and adoration for her..."
She walked back in front of her. "Rise."
Celestia XXIII obediently rose. She stared at the alicorn in acceptance of whatever would come next.
"It is good to see you, sister."
Celestia XXIII had expected rage, disgust, to be banished, to be killed, to be tortured. She had been ready to accept it. Since the letter and the knowledge of Luna's return, she had been ready to suffer for her little ponies. Now that the real, ancient Luna had returned, she had accepted that her disguise would not fool the goddess herself, that she would not be able to masquerade as the real Celestia to someone who had known the real thing back then. She had been ready to pay for her ancestor's crime if it meant her little ponies would continue to live, to be happy. But what she had not expected... was forgiveness and even less acceptance.
"I am princess Luna, half of the voice of the Elements of Harmony. My flesh and my mind are a result of our Elements' touch into pony flesh but ultimately, our body and mind are only perception. While thou may not be the alicorn Celestia, you sacrificed thy flesh and soul to the Elements of Harmony, accepting to be their voice. That your flesh may be covered in chitin instead of a coat does not change thy heart. Thy love is true."
"Princess Luna... what my ancestor did to your sister..."
"Has been atoned for. Thou has banished Discord from this plane of existence through stone and gave thyself as vessels for my sister. You are my sister. Though you may be a new incarnation, thou are true. That thou were birthed from an usurper does not matter. After all, we were birthed from Nightmare Moon and you accepted us with all of your heart. Rise. Be true."
Celestia the XXIIIth slowly rose, staring down at the smaller alicorn. A wide smile appeared on her face. Luna knew that the being standing before her was a fellow pony, not a changeling. The gratitude and love that was all over her face did not lie. Though her form was different, her heart was the same.
"Now, you were going to show us more about Equestria, about how our little ponies changed in the two millenia since we last lived. We would like to rely upon the lifetimes we experienced as the Luna bloodline but those memories are blurry to us. May you kindly?"
"Anything, princess."
"Please, you may simply call us Luna."
"In that case... may you please teach us more about the Elements of Harmony? The lifetimes of my ancestors show me how it felt to use them, to channel them but I want to do so as myself, to truly be worthy of the name I bear and the trust you've given me, Luna."
"An acceptable trade."
The two continued to speak, the tension dying. Celestia XXIII explained to Luna about the spell, of how mother transfered memories to daughters to keep continuity from one Celestia to the next and how it had also been for the Luna bloodline. At first, the stories were serious, about Equestria's great struggles and the difficult decisions taken by the Celestia bloodline but as the hours passed, the two begun to share some less... epic concerns, at least in the eyes of mortals.
To Celestia's shock, it seemed two elements remained timeless. The obsession of mares called Celestia with cake and the sheer inanity and boredom of ponykind's court. Of course, Celestia XXIII vehemently denied the former. The combined memories of twenty-two generations of Celestias and Luna's account of the original alicorn unfortunately did little to appease the changeling queen's ego.
Though... it made Celestia wonder. By channelling the Elements of Harmony and accepting to become the alicorns, the Celestia and Luna bloodlines had effectively become them and when Luna the third had finally died, it seemed that she had become the very material through which the original Luna could be reborn. Does it mean that like Luna III, she hold Celestia's essence within her? Does it mean... that her bloodline's continued existence prevent the return of the original Celestia?
That concern, however, she kept to herself.
Scientific reports by griffins on the pony species.
The pony species are one of the most unique life-forms on Gaia. Being somewhat similar to horses in shape are however, unlike zebras and other equines, more insectoid in appearance, with a chitin body instead of a coat. Ponies, however, will never willingly show this appearance and in fact, if ponies are not allowed to groom themselves magically and renew their better known appearance, they will grow hysterical, often even lashing at one another upon witnessing one another's true forms.
This behaviour is extremely perplexing and seems to come from an incredibly deep fear, probably instinctual, of changelings. Though similar to changelings in a superficial manner, ponies are characterized by their extremely varied color schemes, their more varied magical skills (divided between three types, known as earth ponies, pegasi, and unicorns), the lack of an insect-style hive mind and society structure, and the presence of cutie marks.
It is theorized that the fear of changelings comes from being the changelings' most common prey and source of food ; ponies produce an immense amount of love, which they use to supplement their diet and to power their famed magic of friendship. It is probably also linked with the ponies' tendency to create strange musical numbers known as "heart songs".
It must be noted that despite their insectoid shape, ponies are far closer to equines than to changelings biologically, with a reproduction system based on fertile individuals marrying into either couples or small herds as opposed to the changelings' queen & drone system. No pony queen was ever discovered though conspiracy theorists continue to claim that Celestia may be secretely a pony queen. This fact was debunked as the way the pony population fluctuate and the relationship between Celestia and her court as observed by both ambassadors and spies go are incompatible with the effects of an insect queen's impact. Likewise, ponies are much closer to equines in terms of mental behaviour, lacking the extreme and nearly irrational paranoia and hostility of changelings.
Ponies are difficult to classify, biologically. They are technically mammals as they indeed feed their youngs the expected way but it was discovered that their youngs are born from eggs, though those eggs hatch within the body of female ponies, leading to the illusion of live birth.
Historical note: It is unknown how the true form of ponies was first witnessed. Due to ponies never revealing willingly their true form to anyone, even to fellow ponies, it is probable that the first sightings of their true forms was either from captive ponies forced to forego their appearance grooming ritual until they reverted to their true forms or from individuals unearthing the corpses of deceased ponies, their appearance reverting a few weeks after death in most cases. Historians cannot agree on which case led to the first discovery.
Even today, griffin psychologists are baffled by the ponies' reactions to their own true forms. To anyone else, the ponies are at best only distantly related to changelings, with one confusing a pony for a changeling being akin to confusing a zebra for a buffalo or a donkey for a goat. Thus, it is not quite well-understood why ponies react so violently to each others' true forms, calling one another or even themselves 'changelings'.
Due to the general hysteria that the subject of theit true forms cause, the knowledge of the ponies' true nature is a restricted subject. Those who know of this subject should be wary of spreading such knowledge without express permission from the empire's cabinet lest they cause a diplomatic incident and expose themselves to serious charges.