The Beginning
"To obtain, something of equal value must be lost. This is Alchemy's First Law of Equivalent Exchange."
- Fullmetal Alchemist: Brotherhood
"Twilight...Don't do it!"
"Don't do it... Twilight!"
"Twilight! No! Y'can't!"
"Twilight, stop now while you still can!"
"Twilight please!"
The pleading of her friends, sharp and desperate words of hours before were ringing in her ears.
Princess Twilight Sparkle knew that this was her chance, her only way of saving Equestria and everypony she held dear. It had taken a lot to come this far but for her the cost was worth it. The circle was set, the ingredients placed. All that remained now was to activate it.
Transmutation.
Otherwise known as Alchemy.
One of the most powerful magics in Equestria, it was long thought to have been forgotten. As it turns out, Princess Twilight Sparkle had discovered otherwise and was preparing to commit the ultimate taboo. She had lost the ponies she loved most of all. Teacher, Friend, Sister... now she was the only one left to stand against the darkness and she was afraid. She couldn't do it alone. She had to do this, had to try if not for her own gain than for that of all of Equestria for without the princesses, all hope was lost. The sounds of battle and screams of ponies could be heard even down here in the Canterlot Castle vaults.
For a moment the young Alicorn paused, looking up at where she knew the moon would be shining down by now... if its mistress had not been slain. Then her gaze refocused upon the circle she had drawn upon the stone floor. Written in chalk it was an immense diagram, filled with runes and lines that interconnected to form a hexagonal shape. All it would take was a touch to activate it now that everything was in place.
"I have to do this. It's the only way to save everypony! To save Equestria! I can do this! I know it!" Though her words were strong, there was hesitation there, uncertainty that she pushed aside in favor of what she was about to do.
She took a breath and bowed her head, touching her horn to the skillfully drawn lines. Golden light spread from the point where her horn touched, setting the entire circle aglow. The sensation felt remarkably familiar to when she used the Elements of Harmony. The same rush of power and invincibility. She felt a spark of elation, the magic was working!
Then an ominous air gathered, like a shadow tracing over the light. The circle crackled and flashed, malevolent light swirled around her, the peaceful gold turning dark with unseen rage. Panic laced her features and Twilight tried to back away from the circle as it continued to glow but the shadows gained substance, their equine like shapes surrounding her, grabbing her with teeth and horns, pulling her into the middle of the circle.
What have I done...!? She screamed, saw the light once more and then darkness.
One Year Earlier
The whole of Equestria was celebrating. Twilight Sparkle had just been crowned the newest Princess of Equestria. She who had discovered the true potential of magic was now given a role in which her potential could be used for the good of everypony. Twilight herself was ecstatic but nervous as well. Only a summer ago she had been a normal unicorn, with six new friends in Ponyville. Now she was royalty, living in Canterlot Castle with Celestia, her mentor and Princess Luna. Though she was allowed to go to Ponyville on occasion it was mainly for official business as Princess, not as a civilian. She very much missed her friends back in Ponyville, the five other ponies who were quite literally the incarnations of the other Elements of Harmony.
At the moment she was engaging in her favorite pasttime when royal duties were taken care of. Studying. In this case, she was studying an ancient magical art. It was called Alchemy and according to the texts it had been used in place of traditional magic thousands of years ago. The art involved the manipulation of a material's essence and recreating it into something else entirely. For a Unicorn or an Alicorn, their natural magic was required along with the use of an array known as Transmutation Circle. Other types of ponies simply had to use the array to create the magic.
There were those however who could do this 'Alchemy' without the use of the array. However that came with a terrible price. To be able to use Alchemy without an array, one would have to already have seen a phenomenon known as the Gates of Truth. The appearance varied by the viewer but to most it was a gate of stone, guarded by a strange spirit that acted as both guardian and toll master. He alone took the price that anypony paid after committing the ultimate taboo. He went by many names, but those who had witnessed it said he often went by All, One, or on rare occasion - God.
The idea of such a thing made her shudder, wings trembling in fear. She continued to read and gasped at what the 'taboo' was;
The ultimate taboo, Alchemy's second yet most sacred law is that of pony transmutation. Nopony can be brought back from the dead. It is forbidden and there is no price that can be placed upon a pony's soul. To commit this heinous act requires payment beyond what anypony can hope to achieve. A variation of this process is called Alchemical Rebound and occurs when a pony expends too much energy in the alchemical process. For more on this see EQUIVALENT EXCHANGE.
Shaking her head, Twilight sighed heavily. She would have loved to try such magic for herself, this Alchemy sounded very fascinating. But what if it went wrong? She didn't want to think about that. The earlier chapters of the book did show basic arrays and diagrams for simpler transmutations that eased her slightly. Perhaps those could be tried first, she thought.
She was snapped out of her concentration by the voice of Princess Celestia in her mind. The calm and soothing tone had been a constant companion to her throughout her days in Ponyville. Now it held a hint of command, a royal order of some kind no doubt.
Twilight Sparkle, my faithful student. You are needed in the Meeting Chamber. Come at once. The voice of the Sun Goddess was firm, but not demanding. Rather it was expectant. Rising to her hooves, Twilight left her private chambers and wound her way through the immense corridors of the palace. She still wasn't quite used to how big the place was and had a lot of trouble finding her way to where she was meant to go. Thankfully the guards were kind enough to direct her and she eventually found herself in a circular chamber. It was similar to the throne room but more intimate in scale, with a stone table in the center. Three other Alicorns stood on the other side. Celestia, her sister Luna... and Cadance, a beautiful pale pink Alicorn. Cadance had been the newest Princess before Twilight so they both shared some of the initial discomfort of the role of royalty upon them.
"All three of you? What is this about?" Twilight wondered, hoping she didn't sound too offput by the idea of a meeting when she had been in the middle of some fascinating studies.
"This is your first official Council meeting as Princess, Twilight Sparkle." Celestia replied. "Once every new moon we gather here to discuss the goings-on in Equestria and keep tabs upon the darkness that is ever pressing upon our kingdoms. You will have your own kingdom to rule someday Twilight, but now is not the time. You are still my student and there is much you must learn before then. Now, to the matter at hand - I have heard that you discovered a long forgotten type of magic, Twilight. Is this true?"
Twilight felt sheepish, of course her mentor had been watching through her mind. It was only proper of course that her student be observed to ensure nothing went amiss after her coronation. She nodded, "Yes. I have been studying an ancient art of magic known as Alchemy. Apparently it was once used in place of the magic we know today."
"Indeed, that is true. Alchemy was once used by all ponies so that not just unicorns could be privy to the arcane." Celestia nodded.
"It was a powerful art of the long ago, before the sun was lit and the moon was new." Luna smiled, "It was used for many things - powerful things. Many believe it was what created the Elements of Harmony."
"It was used in the Crystal Empire as well, to build the palace and dig up the crystals used in the city structures. Sombra got ahold of it too..." Cadance shuddered, recalling the terror that particular unicorn had unleashed upon her kingdom.
"The Elements of Harmony? The crystal empire? What else was Alchemy used for?" Twilight was curious now, wondering how the princesses knew of all this before she had even learned of it.
"It was used for many things both good... and evil. All magic has rules Twilight Sparkle, this you know best of all." Celestia said, her voice shifting from soft to stern, "Alchemy has the strictest rules of all. There is one law and it must be obeyed at all costs... to obtain, something of equal value must be lost. That is - what you create with alchemy you must pay a price for. Then of course there is the taboo, what happens when this rule is broken."
Twilight was wide-eyed, even a little afraid. "You mean pony transmutation?"
"Indeed. That type of alchemy is absolutely forbidden. There is no stepping within the realm of the Gods." Celestia stated, her gaze like iron before it simmered down into the softness Twilight knew so well.
"Has anypony ever done that?" Twilight was almost afraid to ask, but she felt like she needed to know this.
"Many moons ago, a pony broke the taboo. She was once a princess who fell in love with a common unicorn. Her parents forbade them from ever meeting, but they did so in secret. Her family discovered this and had the unicorn executed for treason. The princess was distraught, so much so that she tried to bring her beloved back to life through love and magic. Through alchemy. She did what was forbidden and paid the price." Luna chimed in.
"Who was this princess?" Twilight tilted her head to the side slightly. Though the story was new, the main player seemed quite familiar. Love was the catalyst, the desire of her alchemy. Love... the one thing she fed upon. She gasped as recognition suddenly dawned upon her. "You don't mean..."
"Chrysalis. Queen Chrysalis of the Changelings was once Princess Crystala, former ruler of the Crystal Empire. Her changed appearance was the price she paid for trying to bring her lover back. The alchemy twisted her, reshaped her into a husk of her former self..." Cadance shook her head. "Back then, she wasn't a Changeling... she was my elder sister. She told me not to tell our parents and I was naive and agreed. They found her in her chambers... nearly dead and twisted into something else entirely. After that she was exiled, and I never saw her again. Her lover's body was never found either. We think the alchemy destroyed it but... nopony is sure of what really happened. Only she could tell you and she is banished, far away from here."
Twilight couldn't believe what she had just heard. Queen Chrysalis was once a Princess too! It made a lot of sense actually as she had read in a previous book about love potions that told the story of the princess who sought love at all costs. She had tried the potion first only to have it fail spectacularly. That time her parents had let her off with a warning according to the tale. When she used Alchemy, it seemed they had no choice but to intervene.
"I had no idea. Chrysalis..." Twilight suddenly felt a surge of pity for the mare she had met once before, in the heat of battle. It had been Cadance and Shining Armor that had dealt the final blow and she recalled the tears in Cadance's eyes, not just from weakness but at the fact that she had to use magic against her own sister. She couldn't even imagine what that must have been like.
"Yes. Having to banish my older sister... after seeing her for the first time in so many years... it was the most difficult thing I've ever had to do. I can never forget that day, nor will she ever forgive me." Cadance nodded and Twilight could see tears in her sister in law's eyes, just like the ones from those many moons ago.