Nightmare
Princess Celestia has no friends.
She is alone, in the dark tangles of the Everfree Forest. She is caged by the intertwined tree branches, twisted into neat knots around her. Strips of moonlight break through the canopy of leaves above her, creating small white patches on the ground. She bucks and kicks at her barriers, but they do not yield. They do not feel like tree branches on her hooves, but much harder, and they do not bend or yield. With each buck, her hooves sting and burn, and she aches.
There is, of course, no way to escape. A nightmare simply doesn’t work like that. She is confined to her little circle, with some grass and some twigs and leaves in the grass. It’s actually quite comfortable, and she assesses that there is simply no way to leave, so she decides to stop hurting herself and settles in that grass. She looks up at the canopy and smiles at the brilliant pattern, the small scraps of light breaking through the thick foliage.
Princess Celestia cannot wake up.
She tries, of course. There is a certain awareness that one achieves when their psychotic sister continually enters their dreams, manipulating them into their worst nightmares. On most nights, Celestia found that with some willpower and creative thinking, she could break out of this and come into her own consciousness. Yet, the harder she pushes against Nightmare Moon’s magical bonds, the worst it becomes. The ground gets harder, the cracks of light disappear, the cage of branches comes closer, and closer.
Nightmare Moon can sense her resistance. She can feel it tugging against her magic, and she too, fights back. This is her realm, of course, and she knows Celestia’s tricks. She knows that Celestia has been training a new one, a new princess to take over the moon, a princess to defeat The Mare In The Moon on the eve of her return.
The Mare In The Moon. It sounds oddly pleasant, if not a bit haunting. Nightmare scoffs to herself. She prefers the title, The Mare In The Moon, to Luna, the name of weakness and compliance. Of servitude to her sister’s higher power. She hated how Celestia was given this right, this ability to bathe the ponies in a beautiful warmth, a sunlight, and somehow bend them to crave it, to crave her.
Nightmare Moon has no friends.
Perhaps that is the problem, Nightmare wonders, as her branches extend out, twisting around Celestia, tightening around her hooves, her body, her flank, her neck, and she is turning purple from the asphyxiation, as they press tighter and tighter. It is small relief from the fact that Nightmare can’t actually harm the pony in her plush Canterlot bed. It is a small relief from the fact that Celestia has a noble army, and a protegee, and surely others to help that protegee, to access the ancient weapons and mobilize against her.
Whilst Nightmare Moon, forever alone in her realm, her barren kingdom, has nothing but dreams, which Celestia could never wrench out of her grasp. She never wishes to attack her subjects, of course. She loves them, even if they do not love her back. She only wishes to punish Celestia, who once upon a time used the objects that they had constructed together, with the other sisters, and turned against her.
That she had replaced her, replaced the Element of Magic with some nopony in Canterlot who had the powers zapped into her at the last moment, only to be so powerful that her meagre body could not withstand it. Nightmare reflected that Celestia felt that this was her only mistake, that locking her sister in the moon was not really something to be concerned about.
There are no secrets in the realm of dreams.
The trees are gone, the Everfree Forest is gone, and Nightmare Moon feels she is ready. She wishes to see her sister for the first time in a near millenia. They are now in a room together, Celestia is tied to the chair, and Nightmare is sitting in the stool, spinning around with her clipboard. Celestia struggles against the bonds, but she does not wish to. With only the strength that the original Element of Magic had, Nightmare is able to force Celestia to flail, for her legs to thrash and for her head to beat itself against the soft chair.
Nightmare is the psychiatrist, Celestia the patient.
It is a mocking nightmare, sarcastic and sardonic. She always resented how her sister thought she could read her, how she could understand her, how she was always right.
We don’t want to do this, Luna.
This was the hardest part, both ponies knew. Nightmare locked her gaze on Celestia’s, forcing her to stare back. She smirked at Celestia, her dead eyes, the whimper etched across her body. And then she could see.
She could see Equestria, she could see Twilight Sparkle at her desk, she could see the royal guards marching through the halls and Hearth’s Warming Eve celebrations and the auditions held for the Grand Galloping Gala quartet, and Celestia laughing at tea and watching as Cadence played a prank on Prince Bluebood, and she could see Celestia mustering the last of her strength to raise the moon every night, knowing that her sister lay within it.
Luna could taste the guilt on her tongue, Luna could break beyond the fury and feel along with Celestia. But she wrestled herself into control, and Nightmare Moon returned.
“Sister...” Celestia murmured. “You now know what I see, what I feel. Release me.”
“This is my realm, Celestia!” Nightmare roared. “Thou cannot take from me my realm!”
“Luna...” Celestia’s voice was barely above a whisper. “I am not trying to take anything from you, I am trying to help you. I miss you sister, please return for me.”
“Thou locked me in this wretched moon, thou hold me here every day, thou stripped me of every power thou could wrench from my hooves,” Nightmare snarled. “Thine pain is deserved, thine guilt is deserved! Thou stole every day, and I shall steal thine every night.”
“And you have, for so many years,” Celestia said.
“Thou shall not speak, thou shall not utter a word from your vile mouth!” Nightmare cried.
And so Celestia awoke.