1 month later
"Please, Luna, I need you to look into my dreams and see if anything is familiar to you."
Twilight was having a conversation with Luna about the more recent nightmares that have been plaguing her mind, and was practically begging her to help her with the being in them.
"We've told you about 100 times, we haven't been able to see clearly into your mind recently!"
"Yes, but you were in your tower when you were trying to. Can't you get a better chance when you're near me?"
Luna put her hoof to her chin. She hadn't thought of that before. After a while, she finally gave in.
"Very well. Tonight, we shall come and try to enter your dreams again. If it fails, however, then you are on your own."
"Thank you, Luna."
Twilight shook hooves with Luna and went about her own business, tending to political matters, attending meetings about ties with other parts of Equestria, and more boring stuff you would do if you were royalty. Finally, night came and Twilight prepared for Luna's arrival. After a few minutes, Luna finally came, seeming to float into Twilight's bed chambers.
"Here we are. Are you ready, Twilight?"
Twilight nodded her head and laid down on her bed, closing her eyes and entering her dream realm.
Twilight opened her eyes and was revealed with another black void, same as every other time she was here, but this time, she saw Luna walking towards her. When the night goddess reached her, they shook hooves.
"Well, it looks like worked," Twilight observed.
"Yes, it seems it did," Luna responded.
"Congrats on your achievement, princess."
Luna froze as she heard the low voice address her. She turned and shouted to the darkness,
"Who dares speak to us?"
The dark mass appeared and formed the same face that Twilight saw one month ago, speaking to Luna as it did so.
"I dare speak to you. Is that okay, Luna?"
Luna backed up and lowered her head, channeling her magic to her horn.
"You!"
"Yes, me. Were you expecting somepony else?"
Luna shot a magic blast at the face but it dissapated and reappeared behind the two princesses, laughing.
"Ha! Don't even try, Luna! I know all of your tricks and skills, none of which can actually harm me in this state."
Luna turned and stared intently at the face, studying it. Twilight trotted up to Luna's side and spoke to the dark face.
"You know each other?"
"Yes, Luna was actually--"
"Silence!!" Luna screamed at the dark mass, "Why are you here?!"
The face sighed and shook itself, then looked back up to Twilight and stared into her eyes.
"I'm here because I want to speak with you."
It looked back to Luna.
"And while I would love to catch up, Luna, I have to speak to Twilight alone."
The face contorted into a grimace and Luna disappeared, leaving only a pillar of smoke where she once was. It then turned back to Twilight.
"Now, I would like to talk to you about who I am. You see, I'm a being that was created shortly after Celestia and Luna were brought into existence. I was basically their opposite, relishing in and feeding off of the misery, fear, anger, and insanity of other beings. I was able to keep myself hidden quite well, but, eventually, the two princesses found me and banished me from your dimension for eternity. And here I've been for the last 2,000 years, sitting and waiting for the time when I was powerful enough to break free of my prison and return to your world. I'm not strong enough yet, but I'm getting close. That is why I came to you, Twilight."
Twilight backed up and stared at the dark mass in front of her.
"Why did you come to me?"
A small group of black particles removed themselves from the face and smashed together, coming out of it as a large book with a skull marking on the front.
"To give you a warning. This book was one of the many ways I was able to drive other beings insane. Simply reading one page of this book will drive anypony mad, even one as smart as yourself, Twilight. Show this to Celestia and tell her exactly this:"
The face began to dissapate into nothing.
"The end is soon,
Your reign is at an end,
Darkness will emerge from the light,
And your happiness you can never again mend."
Twilight woke up screaming and Luna put her hoof over the screaming filly's mouth, putting the room in silence once more.
"It's alright, Twilight, you're awake now. What did he tell you?"
Twilight hopped out of her bed and started towards the door.
"I need to speak to Celestia, now."
She spotted the book lying on her bed and quickly grabbed it, afterwards making her way to Celestia's bed chambers, Luna following closely behind. As soon as she knocked on the door, Celestia opened it and looked at Twilight.
"Why, hello, Twilight. How are--"
She stoopped as soon as she saw the serious and grave look on Twilight's face. Celestia moved to the side and allowed Twilight and Luna to enter, all three of them standing in the middle of the room.
"What happened? Does it have something to do with your nightmares?"
Twilight nodded and pulled out the book, putting it in front of her.
"Yes, it does have something to do with my nightmares. The thing that I told you about that visited me that one time appeared again, but this time it gave me this book and told me to give you a message."
She repeated the message to Celestia, making her go wide-eyed. She started pacing around the room looking very unsettled and actually afraid.
"This is bad, this is very, very, very bad."
She trotted over to Luna.
"I thought that banish spell was supposed to last for eternity. What happened?"
Luna shrugged. "Your guess is as good as mine, sister."
Twilight walked over to Celestia. "What does this mean, princess?"
Celestia looked at Twilight with a look that made her feel so worried, she began to fear the worst.
"Something's coming. Something powerful, and I don't know if we can stop it again."
Luna stepped in, adding to Celestia's explanation. "And if we can't stop it, we might as well say good-bye to Equestria."