Beyond the verdant mountains of central Equestria lay the small town of Hoofberg. Within this town lived a certain pony. This unicorn was a member of a very prominent family, but she was never happy. She had all the wealth and status she could wish for, yet she was constantly deprived of satisfaction. Truth be told, she hated the money, the status, and all ponies that weren't exactly like her and who didn't share her wild, farfetched beliefs.
Her hatred grew to include all Earth ponies, because she saw them as not having the mental capacity to do anything but work. She found them to be dumb and inferior. She didn't take into account that the town she called home had been started by a group of Earth ponies. She also didn't take into account that without the Earth ponies and their hard work on their farms, Hoofberg as she knew it wouldn't exist at all.
Her parents were incredibly successful in the horseshoe business. They had amassed a great wealth, but were extremely philanthropic with it. They were generous ponies, even earning a distinction from Princess Twilight and Rarity, the unicorn who embodied the element of generosity, as two of the most generous ponies in Equestria. True to their form, they did not flaunt this award in front of the other ponies, but were quietly grateful for it and continued their charitable work in and around Hoofberg.
But Sapphira hated it all. She wanted all the Earth ponies destroyed. She believed that they were constantly taking jobs away from unicorns who deserved them more. She didn't stop to think that qualifications or experience were taken into account when somepony hired another pony. She only looked at the outside of her fellow ponies, and she was hurting because of it.
Somewhat miraculously, she did manage to have one friend, a unicorn named Rose. Rose was a dark soul, spreading malicious rumors about the Earth ponies of Hoofberg. Now, dear reader, you can see where Sapphira got her viciousness from. She had met Rose at a small meeting of a secret society they were both a part of. This society's name was "Unicornis Vel Dominationem," which translated means "Unicorn Domination," and they had one goal: kill every last Earth pony and Pegasus in Equestria.
The scariest part of that prospect was that they had been successful in their endeavors more and more frequently. A string of mysterious murders around Hoofberg had been assigned to them, and they had happily taken credit for them. They never met in public, only in private, and their meetings were so mysterious and off the grid that new members were sent to live in the woods for a week after being initiated so they wouldn't get caught by the local police.
It was here that Rose and Sapphira first struck up a conversation, the former being upset at an Earth pony who had dealt her family a bad business deal, and the latter being upset at what she deemed the inferiority of Earth ponies. They also had malicious thoughts about pegasi, believing them to be demented winged mutated hybrids of ponies and birds.
It was only a few months prior that they had both participated in their first murder. It was an innocent pegasi foal, only a few months away from graduating flight school. They had cut off her wings as a trophy for the group and then driven their horns simultaneously through her chest. They both laughed as her blood stained the ground under their hooves. Having finished their disgusting and loathsome deed, they returned home and slept calmly.
Rose's mind was completely gone. Ironically, from the time she was a foal, her parents had raised her to love and respect other ponies. But the bad dealings of one Earth pony, coupled with the demented teachings of "Unicornis Vel Dominationem," had rendered her mind nothing more than a pile of mush. Insanity was her new friend, and she embraced it with reckless abandon.
But while she was definitely scary, it was Sapphira who was the scarier pony. She refused to give in to the same crazy cravings that her best friend had. She retained all her sanity and intelligence, which made her even more dangerous to the ponies around her. Soon, she developed a lust for power and wanted to rule Equestria. She wanted all of the princesses dead, for what were they but, in her mind, impure hybrids of Earth ponies, pegasi, and unicorns?
The creaky wheels of her mind began rattling as the days went by, and soon enough, she had developed a plan to kill Celestia and take over Equestria. Or, as ponies everywhere will soon call it…Unicornistan! With those evil thoughts, she and Rose set about making plans to raise an army of unicorns to storm Canterlot and take over Equestria.
Now, in Maddock's case, he had the help of three of the princesses to eradicate his prejudice and hatred. But in Sapphira's case, she had nopony there to help her and to show her what true friendship really is. Rose had been the only pony she had ever been friendly towards, and she wasn't about to stop. Her parents had noticed that the quiet, yet sweet pony they once knew was turning dark and cold. They tried to help her, but to no avail. She swept them under the rug and, quite literally, washed her hooves of them.
Hoofberg had been going through a bit of a rough stretch recently, as the ground had yielded very few crops that season. She and Rose capitalized on this and created propagandistic posters that blamed the Earth ponies for the town's problems. They would show this at their society meetings. Unsurprisingly enough, the members of the society praised Sapphira and Rose for their cunning ways.
Being underground was essential to their plan for dominating Equestria, so they remained secretive with their actions. Their first target was Ponyville, more specifically Princess Twilight and the School of Friendship. They planned to attack the school, kill the Earth ponies and pegasi, and force the unicorns to make a choice between death or joining their group. Plans were quickly laid, and a few nights later, "Unicornis Vel Dominationem" marched out of Hoofberg toward Ponyville under cover of darkness