Harmony's Peril

"Princess..." a voice whispered. Twilight groaned in response. "Princess you must wake." Twilight's eyes shot open, and when her vision came into focus she saw an elderly light brown unicorn mare standing beside her bed.

"Book Mark?" Twilight asked groggily, recognizing the royal librarian. "Ugh what time is it? Is it morning? Am I late?!"

Book Mark chuckled. "Earnest as ever Twilight. If it was morning would it matter? The sun no longer shines. As for the time... it has only been a few hours."

Twilight rubbed her bleary eyes and yawned. "It's the middle of the night? Um... then why'd you wake me up?"

Twilight had known the royal librarian since she was a foal. She had spent so much time in the library that Book Mark even gave her her own special reading room, and sorted out specific titles that Twilight might like. The librarian treated Twilight like a grandchild, and often imparted to her the wisdom she had learned over decades of reading. One thing Twilight knew, was that Book Mark loved her sleep... and it was odd that she was awake in the middle of the night.

"So you may learn about the foe you face." Book Mark replied as she adjusted her thick glasses.

"How did you know-"

Book Mark waved a dismissive hoof. "The walls have ears Twilight. Rumor spreads around here pretty quickly. Now come on, the answers we seek are in the library."

Twilight slipped out of bed and followed the librarian out the door. Book Mark magically lit her horn, lighting up the dark hallways. They trotted quietly, careful to make sure their hoofsteps didn't wake anyone.

The light cast eerie shadows along the walls, and had Twilight been a foal she might've even been scared. She watched her own shadow trot perpendicular to her, matching her every move. Twilight glanced at Book Mark trotting ahead of her. Her shadow seemed... distorted, as if it were the shadow of something much larger. Before Twilight could make it out, Book Mark dimmed the light. "We're here."

Twilight realized she was being silly. Shadows scared foals not an alicorn princess. Now quesadillas... those were scary. Book Mark levitated her keys out of her nightgown toward the door. The wooden door unlocked with small click and swung open. "Um, don't we need the light?" Twilight asked.

Book Mark pointed to a guard who was fast asleep inside the library. "Wouldn't want to disturb his nap."

Twilight followed the librarian inside, quietly sneaking past the guard. They went deeper and deeper into the ancient library, until they reached a dark gated section. Book Mark levitated her keys and unlocked the gate, trotting past it. Twilight hesitated to follow, and her guide turned around with a confused look.

"That's the dark magic section. Princess Celestia said never to go in there..." Twilight whispered.

Book Mark smiled, wrinkles creasing her time worn face. "But the answers you seek are here dear. Isn't it important to you to find out who's behind all this?"

"But the Princess-"

"Twilight." the librarian said patiently. "You are no longer a student, you are a princess now. You must make your own decisions and judgements based on what you think is good for Equestria. When the answers are just a few steps away, will you let them slip through your hooves?"

Book Mark had a point. Finding out who poisoned the tree would bring her one step closer to solving all this. Princess Celestia had said Twilight wasn't even ready, yet here Twilight was, just a few feet from answers. The Princess had said not to look into the dark magic section, but surely she would be okay with it now. Equestria itself was on the line, and Twilight had a duty to save it. Determinedly, Twilight trotted past the gate.

"We've got to find out what burned those cloven hoof marks into the tree." Twilight said.

"Perhaps this might help?" Book Mark levitated a large dusty black tome onto the floor. Twilight lit her horn, and peered at the cover. It read: "Dark Marks and Symbols". She used her magic to flip it open to the 'C' section and flipped until she found the entry she wanted.

Cloven Hooves

Description: This mark is often burned into wood and is usually black in color. It belongs to an eldritch creature known as the Fiend, who is not of this plane of existence. He leaves it as a warning or a calling card, to make beings aware of his presence or involvement. It is advised to avoid places marked with this symbol at all costs, lest he exert his wrath upon trespassers.

Twilight felt her stomach turn slightly, but decided to press on.

The Fiend goes by many names as he visits different worlds across the multiverse. He is known as Satan, Lucifer, the Devil and Old Nick among other epithets. The force of evil incarnate, he seeks to corrupt the hearts and minds of ponies, humans and all creatures alike. Many worlds have fallen to his influence, becoming demented hellish places where good is fleeting to nonexistent.

Thousands of years ago, the Fiend ruled Equestria in a state of misery. His numerous demonic servants, especially the windigos, caused untold suffering. However the first friendship between Clover the clever, Private Pansy and Smart Cookie, weakened the Fiend's power so much that he fled our world and his servants were scattered to the ends of the planet. It is unknown why one friendship was so powerful as to defeat the Devil himself. What is known is that soon after, Princess Celestia and Luna took charge of Equestria and the Fiend has not returned since.

Suddenly what Princess Celestia said made sense. "When the balance unravels, evil will take its place."

Powers: Records from the time of the Fiend's rule are sparse, however it has been noted that the Fiend is capable of anything. He can warp time and space to his own desire, on a planet wide scale. His very presence causes feelings of hatred and anger to surface. Despite his great power, he prefers instead to use trickery and guile to get his way. Often he watches his targets for a time, years even, manipulating things behind the scenes. He may shapeshift into someone familiar and coerce a pony into doing what he wants. Though he can create a perfect likeness of a pony, there are certain things he cannot hide. His shadow is that of a large beast, and will follow him no matter what his shape. His eyes...

Twilight raised her head in alarm. The shadow. Slowly she turned around to look at her companion. Book Mark had a sinister grin on her face, her teeth sharp and pointed like predator's. Her eyes weren't ringed with their usual brown, but were instead were pure black. "I'll be watching Twilight. Always watching." She vanished into black smoke.

Behind her, Twilight heard urgent galloping as though multiple ponies were rushing to the scene. She turned around and saw the blackened forms of Celestia and Luna, and the now fully awake guard panting with exhaustion. "I'm very disappointed in you Twilight." Celestia said angrily.

"But I-"

"I specifically said never to read anything in this section. Now you go behind my back and-" Celestia went into a coughing fit.

"Your Highness!" the guard supported her. Luna began wheezing. She closed her eyes and fell to the floor.

"Luna no!" Celestia croaked.

"Princess wait let me help!" Twilight rushed over to them. "Please I'm sorry I didn't mean to-"

"T-Twilight I..." Celestia collapsed, her eyes sliding closed.

"No!" Twilight cried.

"Help! We need a medic! The Princesses have fainted!" the guard yelled. Twilight felt tears roll down her cheeks, as she looked down at the mentor she had betrayed.