Celestia and Luna watched the train, packed full of refugees, flee from the domed empire while they flew high above. The Crystal Heart was safely in the care of Cadance and Shining Armor, and the two vowed to return to the Empire as soon as possible. They didn't want it to become another ruin of legend lost to time. And thus, the princesses saw the violent blizzards of the tundra slowly encroach upon the kingdom until it was engulfed in the white, tumultuous clouds of white when the dome fell.
Luna shook her head in disappointment. "A pointless loss," she lamented. There was silence exchanged between the two sisters, but Luna wasn't going to remain silent. "I grow tired of this traveler's behavior. He acts without coming through us first."
"I agree," Celestia responded. "But we can't oppose him directly. I fear that our behavior might cause him to grow frustrated and destroy our world like he has already mentioned."
Luna grit her teeth and looked down in defeat. The two spun around to look at the train when they heard a disturbing noise. With a loud screech, everypony was thrown forward in the train cars and left groaning and in pain in large piles. Cadance pushed herself out of one of the piles and massaged her left shoulder.
"What's happening? What's going on?"
Everypony, please get out of the train. I have a solution for your problem.
"That's Twilight," Cadance spoke aloud.
The mare helped everypony onto their hooves and brought them to the snowy ground outside, where everyone was still reeling from the sudden break. Shining galloped up to his wife with Flurry held in his magic, panting hard.
"I guess staying with me always causes issues," he joked between gasps. He looked up to see Twilight's approaching the train at high speeds. "What is she talking about?"
Luna and Celestia landed next to the couple, prompting Flurry to wave at Luna and get grumpy when she ignored her. Twilight, on the other hoof, flew in too fast and, although she did her best to catch herself from falling, the mare ultimate skid along the ground before faceplanting and stopping at Celestia's hoof.
"Oh my goodness. Are you alright, Twilight?" Celestia asked in concern.
She lifted the lavender alicorn back onto her hooves, allowing Twilight to regain her bearings and shake the snow off of her face.
"I'm okay," she mumbled. Her eyes shot open. "I have a solution to what the traveler said about you all having Sombra in your souls!" she blurted.
"WE WHAT?!" Cadance and Shining bellowed.
Flurry cried from the sudden loud noise next to her ears, forcing Cadance to calm her down and coo her.
"He gave me what he promised. A spell to save everypony," she spoke quickly and enthusiastically.
Celestia was skeptical. "Are you sure we can trust this spell? And where did you get it from?"
Twilight's heaved panting wasn't helping her formulate her sentences properly. Her wings hurt greatly and she was about to pass out. Before she had time, however, some of the crystal ponies started noticing parts of their bodies turning black, giving Twilight the excuse she needed to use the spell.
"We don't have time," she yelled. "It's either this or they disappear forever." Twilight was on the verge of breaking, and her voice was reflecting that. "I don't want to lose my family."
The pleading eyes of Twilight stared deep into Celestia's stern and hardy ones, but the white alicorn still conceded. "Very well," Celestia sighed. "Go ahead."
The lavender alicorn pointed to both of the alicorns. "I actually need your help to perform this spell."
Cadance stepped forward. "What about me?" she asked.
Twilight shook her head. "No. You're affected too. You need to be under the effect of the spell."
"All of us?" Cadance asked. Twilight nodded, and the pink pony looked around to Shining and her people. "Very well."
Shining put a hoof to Twilight's shoulder and put his forehead against hers, making their horns cross. It was much easier with her being his height now. "I trust you, little sister," he said.
Twilight's spirits were lifted, and she turned to the other two alicorns. All three took to the sky, and Twilight began to focus the magic in her horn.
"I just need you to give me as much magic as possible to keep the spell steady, alright?" she said.
"Did you even try out this spell?" Luna asked. Twilight dropped her head and smiled sheepishly at the mare who rolled her eyes and gave an exasperated expression in return. "Marvelous. Put the fate of our citizens in the hooves of an untested spell."
"Your berating isn't helping, Luna," Celestia quipped.
The two created beams of gentle light; one of blue and one of white, that melded into each other and into the middle of Twilight's back. For a few seconds, nothing happened, and everypony was doubtful if anything was going to happen. Eventually, Twilight's spell finally began to take effect, and while the two alicorn sisters watched her, they saw something transparent engulf Twilight. Like an echo or a window. The transparent afterimage took on the appearance of a pony with spikes protruding from beneath their flesh, and wraps of brown cloth around amputated limbs replaced with weaponry and tools. She was even gifted with two mouths and metal plate bolted onto her head to cover her eyes permanently. The magic took on a brownish hue with threads of gray appearing in the swirling vortex of energy expanding around Twilight's horn.
"Is that...?" Luna whispered.
Celestia's eyes were filled with a bright rage at the sight. "Yes. It's soul magic, but...it's twisted, somehow."
Above the trains, reality started to crack. Space blew outwards into several hundred small squares leaving way to a space containing a swirling vortex of blacks and white from which a faceless figure came forth. Everyone watched in horror as its four hands reached out and grabbed the edges of the vortex. It looked around first, curious as to its location, and its head 'looked' towards the three alicorns after it was done scouting.
"What in Equestria is that abomination. It dominates my field of vision," Luna cursed.
Celestia was speechless. "What did he bring to my Equestria?" she thought.
The entity looked down upon the terrified creatures before it and silently reached an arm out to the space above them. It immediately tightened its grip to grab hundreds upon hundreds of string attached to the creatures below. The crystal ponies froze in place, allowing the faceless entity to use another arm to tug on the them and pull out ghostly apparitions of said affected ponies.
"What is it doing?!" Celestia shouted. "We must stop the spell!"
"No!" Twilight pleaded. "This is how it works!"
"Twilight, I can't in good conscious let--"
"Look!" Luna interjected loudly.
Small black clouds were swirling along the ghostly apparitions that the creature didn't hesitate to squeeze off of each and every one of them at once with its third arm and keep them in its clenched fist. Each of the clouds screeched in horor and rage as the entity sucked them into an inescapable hold. It inspected its hand, nodded, then used its fourth to properly return the apparitions to the owners. Once its first hand let go, the strings disappeared and everyone started moving about fearfully, unaware of what just transpired. The faceless creature faded back into the void, and the squares returned back to their places until there was no sign that they anything had ever happened to the space to begin with. All the magic used dispelled, causing the afterimages around Twilight to vanish. Twilight and the two alicorn sisters collapsed into the snow far below, causing the crystal ponies to rush to them and prop them up.
"Twilight," Cadance started. "You're going to have to tell me exactly what that was."
"And we have much to talk about," Celestia spoke threateningly.
Her angered face and furious -yet tired- eyes melted through Twilight, and she felt a great fear overcome her. The ponies took them inside the cars while the rest tried to assess what had just happened. Celestia was propped up on a chair and given a large blanket to cover herself with, as did the other two. Luna chose to stand and lean against the stall door, however, while Twilight remained on the floor. There was but tense silence exchanged between the three, and neither party felt inclined to start talking, but Celestia's anger broke through her fatigue, if only briefly.
"Twilight," she spoke harshly. "What you used was soul magic."
Twilight tapped her hooves on the ground. "And? I didn't know it would summon--"
"That's not the point," Luna interrupted. "You use forbidden magics that can cause great harm to both the receiver AND the caster."
Twilight blinked innocently. "They were forbidden?" She looked to Celestia. "But I never saw anything about soul magic."
Luna deadpanned to her sister and gave a playful, sarcastic smile. "Sister. Surely you didn't remove any and all mentions of such a thing." Her voice was serene and soothing, but Celestia was made uncomfortable by it.
She fidgeted in place. "I..."
"Are you serious?!" Luna exploded. "I was trapped for a thousand years, and you didn't think to make ponies aware of its dangers?!"
"Destroying any and all references to soul magic was sufficient to destroy its knowledge among the populace," Celestia replied with barely contained rage.
"And in the process, those that rediscover it by chance are chased after and punished and don't know why, because YOU never taught them!"
"But I--"
"Am punishing them for a crime they aren't even aware they committed!" Luna rebutted. "That's not how that works, sister. I understand the good intentions you had initially, but teaching about the issue rather than outright banning it CAN be a more sufficient deterrent." She shook her head in disappointment. "Who knows how many ponies practice this magic without even knowing what it is, likely thinking that they're prodigies of magic having discovered something entirely new."
"Except those incidents are far and few between." She used her legs to force herself to move on the seat and face Luna directly. "If you have vines invading your yard, you don't tug on the leaves and the few strings of the plant growing about the area. You track down the root then clip it off. The whole plants dies later on, facilitating your removal of it." She was about to continue the argument but refrained from doing so. "More importantly, Twilight, what exactly did the traveler give to you?"
"Um..." Twilight couldn't make eye contact. "A spells used by the Sins of Eldromac."
"The what?" Luna said with disbelief.
"The Sins of Eldromac!" Twilight insisted. "They apparently had lots of work with this kin of thing, and the traveler told me that he something that could save everypony if I worked fast enough with the farm project."
Celestia rubbed her temples and groaned from fatigue.
"Well, we can't fault you for what you thought was best-" Luna turned to Celestia. "-sister," she spat angrily. "But without knowing what that gigantic entity was or what it did, we can't in good conscious leave the crystal ponies unsupervised."
"At least it left the Crystal Heart alone," Celestia spoke with relief. "Most 'evil' beings would go straight for it because of the powers it holds." She massaged the top of her head with a hoof. "I still want to know what that thing was and why it drained so much of her energy so quickly...and why it seemed so curious when it came through." A shiver ran through her body. "I don't like it."
Further away, the black mass that the faceless being crushed with its grip gestated. Several days passed by before it all clumped together into a morphing mass of indiscernible shapes. Gradually, but surely, it started to stabilize and sculpt itself. It rose upon wobbly legs, each supporting the as-of-yet unstable mass of black clouds. Next came a long, bushy tail, then a back, then a neck, and then the head.
The black fur of the tail and mane were linked by a path of flowing mist along the spine. Their body became assorted with a variety of faint white dots imitating the stars in the sky, and their iris was a purplish color. The whole right side of their face, however, took on a concave appearance of sparkling amethyst crystals. Its whole body followed the sparkling with every movement it made in an attempt to walk. It faceplanted into the puffs of snow before it, forcing it to look at the freezing substance with curiosity. It sat up and pushed against the snow with a hoof, hearing a crunching sound. It repeated the action several more times, finding amusement with each crush, but there was more to discover. It felt it, and so it stood up and obeyed its instinct, and faceplanted into the snow again. It didn't know how to walk. It would learn.