"GO AWAY!" She screamed. "I HATE YOU!!" She ran off as fast as her hooves could carry her. Celestia could only stare in disbelief. What was that? Did her faithful student just reject her? No, she's just upset by her...sudden transition. Yes, that was it, right?
"Twilight?!" She called. "Twilight!!!" She could hear the clack of hooves on the tile growing quieter "Twilight, come back!!! Twilight...? Twilight!!!" She could have stopped her. She could have closed the door so she couldn't escape. Her eyes became blurry. Why did she leave like that? She thought she learned better than that. What ever happened to not judging a book by it's cover, the lesson she learned when she befriended Zecora? She called again, but couldn't hear her student's footsteps any longer.
I told you it would not go over well with her.
"Sh-shut up... You did something to her..."
I did no such thing. She needed to see what we are, so she saw.
Celestia sobbed. "What she saw... was a p-parasite, not a mutual symbiosis... you did something to her, blast it!"
you said your gentle gaze would be enough.
"SHUT UP!!!" She said no more, falling to the floor in a wailing wreck.
The creature within remained silent for a moment. When it spoke, it's words were less accusing this time. Celestia, you know I have always wanted power. Have you ever thought of why?
Celestia said nothing.
I've never had any true power of my own, and even in connection with others, I still wasn't very strong. Haven't you ever felt weak? Nightmare was about to continue, when the door to Celestia's chambers burst open.
"Sister!" Luna shouted. "Thou hast hidden thy face from us for long enough! Prey tell, why wouldst thou make our best friend weep so?!" She stepped out to the balcony, rightfully upset. Celestia refused to look at her, continuing to sob weakly. So now Luna saw her as a monster, didn't she? She was a fool to think that her new look would be well received. She gave in to defeat.
"Go ahead and kill me," she whimpered. "Just make it quick, would you?"
Are you mad? What kind of good will that do you? Celestia stood up, facing her sister to receive whatever punishment she had in store for her.
Instead of the furious gaze she expected, her eyes met with gentle ones. "We thought you would know better than to associate with things that only seek power." Celestia stared in confusion, to which Luna chucked. "Dearest sister, it seems you have wandered into territory that only we are familiar with." She beckoned her closer. "Tell us, how does it feel to have a second voice within your mind? We would care to know from...a different perspective."
...
Twilight slowly stepped down the hallway, preferably away from the creature that stole her mentor's body. She hated that creature which forced itself into her body. She hated herself for not seeing the signs sooner. She hated Celestia for not being the perfect teacher she always wanted. She hated her friends-Wait, what's wrong with me? how could I hate Princess Celestia? She turned to look at a mirror she was about to pass by.
To her horror she saw not her purple colors gleaming back into her eyes, but a grey coat and grey mane. Her legs quivered under her own weight. And it happened so quickly, too. How could I have let myself give into this? Twilight, Nightmare moon was right. You are a little foal. A stupid selfish little FOAL! She threw her hoof at the mirror, shattering the glass. The shards cut her skin, but she didn't care. it was only proper punishment for stupid little foals.
Twilight climbed up a flight of stairs, wincing at the cuts stretching on her back. At least her blood was red, wasn't it? She wanted to leave. She wasn't sure where, just out of Equestria. But the nightmare had control over the other nations, and even the entire world, didn't it? It gambled for power, and it won. Now it wants power over her as well. She wasn't going to let that happen, she would die before that happened. In fact, dying seemed like a good idea. reaching the top of the tower, she looked upon Equestria. The day refused to give way for the night, didn't it? There was not a time when the sun didn't shine upon the union, because the union was the world. The only way to leave the union was to die, so die she would.
She closed her eyes and leaped off the tower, content that nothing would be able to control her. Nopony would miss her anyway.
Her vision was surrounded by the glow of fire, and her decent stopped.