Celestia was in a panic as she flew across the land her mane and tale were singed and her coat had her a few burn spots on her. Behind her a huge beam of fire followed her. It was destroying everything in it's path. Celestia couldn't look back as she knew it would kill her. Behind her the beam disappeared and behind it was the source of it. That being a huge centaur almost as big as her castle.
The centaur known as Tirek could only laugh as he chased the alicorn. "You can't run or fly from me Celestia. You can't even hide."
Celestia continued flying until she flew through Ghastly gorge. Tirek was soon stopped by the huge cave eels that occupied the caves. He was soon in combat with them and he was slowly winning. Celestia knew that would at least distract him long enough for her to find a place to hide. Eventually she found an unoccupied cave. It would make a good hiding spot for now.
She glanced out and saw Tirek defeating the eels only for him to slowly trot forward through the gorge. Celestia did her best to stay quiet but when she attempted to go deeper into the cave she had the feeling she wasn't alone in that cave. At some point she smelled something. It smelled like cinnamon. She then saw something move within the darkness. She now wanted to leave but she knew it would resulted in Tirek finding her. Using what was left of her magic she lit up the cave only for her to come face to face with the skull of a horse.
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Celestia awoke with a scream. Two guards suddenly burst through the door followed by her sister Luna. "Sister I saw your dream. Are you alright?"
Celestia's rapid breathing slowed to a calm pace. "Yes Luna I'm fine. But I fear the world won't be for long. Did you see what I saw in the cave?"
Luna went from concern to confusion. "Cave? I only saw Tirek and those eels fighting? What did I miss?"
Celestia said nothing as she got out of bed and walked to the balcony. The moon was still up but she saw the clock and knew morning was coming very soon. Luna joined her on the balcony. "Luna let me ask you something. If you had to choose between a young hero like Twilight and a hero from far long ago what would you pick?"
"What kind of question is that? Twilight would always be the one. You gave her those wings for all she did and learn."
"I did but I fear what might come here maybe too much for her to handle."
"Agree if Tirek has gained enough power then he might be too powerful. Is this about that other monster you saw? What do you know about him?"
"He's somewhat of an old folklore. He first appeared sometime after your banishment. He comes when there is impending doom and most of the time intervenes. I haven't seen him for a long time."
"When was the last time you saw him?" asked Luna.
"The night before you came back as the Nightmare. I hope he can help us."
"And if he shows up too late? Who else can we rely on?"
"Call this crazy, but maybe Discord can help if Fluttershy reformed him right."
"You're right sister, that is crazy."
Both their horns glowed and soon the moon went down followed by the sun coming up. It was the start of another day. Further away from the castle a horse skull on a long neck stuck out of a forest and watched the sunrise.