The Curious Instance of Twilight Sparkle

The royal guard clambered into the room, "step aside" one of the guards coarsely said to Spike. Spike did as he was told not wanting to make any trouble. The royal guard quickly got to work seeing if anything could be deduced of her condition, they checked her breathing which was slow and in short ragged breaths. She was not responsive to any external stimuli so they thought she must be unconscious. After seeing if her neck or any of her bones were broken did they decide to move her. They picked her up and quickly shuffled out of the room, Spike waddling along beside them.

The guards quickly took her to Princess Celestia, who at the moment they walked in was relaxing in her study. When the guards walked in carrying Twilight, Princess Celestia dropped the cup of tea she was drinking and ran over to her student. "What happened?" Celestia demanded. "I am sorry your highness, but I do not know." Princess Celestia used her magic to examine Twilight Sparkle. Upon further examination in turned out that Twilight had been cursed. “Where did you find her asked Princess Celestia?” “We found her in an abandoned part of the archives, your highness.” Thinking to herself she wondered what could have possibly happened to Twilight, she then remembered.

Centuries before, shortly after she had banished Princess Luna to the moon using the elements of harmony another evil appeared. This evil didn't have a physical form, it instead possessed the bodies of ponies and used them to commit horrific acts such as cannibalism and rape after the evil left these ponies they would wither up and die. Countless numbers of her subjects died before she figured out what was happening and how to act. She sealed the evil away in a book protected by powerful enchantments that it would never be able to break, she then hid it away in the Canterlot archives thinking that it would never break free. But over time it seems that the evil imprisoned inside the book had eaten away at most of the enchantments and corrupted many more. But when Twilight tampered with the invisibility enchantment that had been put over the book, it must have used this slight weakening in its magical bonds to lash out at Twilight.

Celestia knew that the only thing she could do was seal it away again, the evil that resided in the tome was to powerful to vanquish even with all four alicorn princesses and the elements of harmony. Her train of thought was interrupted when Spike asked "will Twilight be all right?" Princess Celestia pondered his question for a moment, because Twilight had only briefly come in contact with it she would remain comatose for up to a month and her sanity might be slightly affected but she probably would make a full recovery. After thinking her answer over she said to Spike "she may be in a comatose state for a while and she might be a bit different when she wakes up but other than that she should be back to normal in about 3 months.

But there was one thing Princess Celestia didn't tell him, that someone attacked or possessed by this evil who survive sometimes gains an affinity for dark magic. That is what happened with King Sombra and the Crystal Empire.