Somnovore
Everypony has aspects of themselves that they keep hidden, cloaked behind mirth, or silence, or isolation. It's what we do in these secret places of the heart that defines us, that makes us who and what we are. Everypony is different. One's secret keep is warm, kind, and gentle, and the stronghold of another is dark and disturbing.
And I see them all.
Nopony remains cloaked in their dreams.
When I was young, I was so eager to give everything in the service of others. Had it not been for the intervention of Harmony itself, I would have died fighting against Discord, but I regarded it as my place to do so. One might have suspected that I would learn from such an experience, but apparently this was not the case, for when the chance came to take on the mantle of a Dreamwalker I leapt to it, not knowing or caring what it would cost me to do so.
I am proud beyond words of what it is I do. Our kind is a sacred order, always limited to a single pony at a time, blessed by Harmony itself to guard Equestrians from the ways magic would twist and warp their nightmares into doing them harm. In order to do so, though, we must take the nightmares into ourselves for the good of our charges. This is why we who perform this task have always referred to ourselves by another name.
We are the Dream-Eaters.
It is not every night that I am called upon to perform my task, but it is enough. I have time set aside every night for my private use, where no pony may disturb me for any reason. I set the most stringent penalties against this edict, lest a random guard decide that the risk was worth it. It is in this time that I go to the dreamscape, to walk among the dreams of my subjects, as I do now.
They do not know I am there. I see all even as I am unseen. The sight and sensation of it is indescribable. Everypony's basest natures, deepest desires, and hidden wishes; laid bare for my eyes. It is easy to see why our kind live in such isolation, never letting anypony else know who we are and what we do. Mental magics of any kind are suspect and distrusted by many, and for good reason. I have the ability to alter any dream as I see fit, to guide or to distract, so long as I am prepared to accept the consequences of my actions.
For this reason, I must pick and choose carefully on whose behalf I will intervene, and for what reasons. By altering the dreams of another, I am forced to experience the dream through the sleeping eyes of that pony in their place.
In my mind, I can feel the pull. I know well the signature of an encroaching nightmare, one that might require my attention and intervention. Leaving my musing thoughts behind, I fly motionlessly to the restless mind in question.
It belongs to a filly I know, the younger sister of one of the Elements of Harmony. I resist a sigh as I delve into the dream, to watch silently from the shadows of the filly's mind. I could feel my conscience standing up, prodding me forward as the scene unfolded, that same voice that tried to prompt me every time I knew I should be doing something I dreaded.
The white-coated filly was screaming at her sister.
"You did this on purpose! Stealing the spotlight like you always do!"
Be strong, Luna. Help her.
I felt a cringing pain in my heart. This was a scenario I knew all too well, too deeply.
You have to help this filly. You know the consequences for her if you do not.
"Stop! Why do you have to ruin everything?!"
Don't let her fall...
Steeling myself, I released my power, freezing the dream in place and sweeping it away entirely, opening up to the filly and revealing myself to her. This scared, hurt little soul...
She quickly realized the error of her ways once I showed her the true sight of her situation, swearing that she could make it all right again. I left her to her sleep, praying that it would be so. I knew all too well the pain of holding in anger against a sibling. And I would know that pain again through the filly's eyes tonight for what I did in helping her make amends.
I tried to ready myself for the nightmare. This was my most common battleground. My experience allowed me to survive where every other resource would fail. Magic was useless, and physical strength meaningless. Only the strength of your mind could hold you up under the relentless barrage of emotion brought on by dreams. The dreams of the young are the hardest to bear, because they experience their emotions so much more strongly than the old, not having cause to harden themselves against pain and disappointment.
I felt the nightmare settle in around me. I felt cold, almost clammy, as though the dream itself were formed from a dark, heavy mist. Much like those mists, the dream coalesced around me, gradually firming and forming itself into the dreamscape I would be trapped in.
This is not the dream...
Around me was not the interior of the Carousel Boutique I had expected. It was a much older memory. My blood ran cold as I found myself standing in my own past.
Oh, Harmony, please not this...
I was barely out of my teenaged seasons as I stood, facing down my sister. Mentally, I shied away, overwhelmed by the sheer pain I could feel around me. Anger, betrayal, and pride radiated from me like the sun my sister commanded, and much like I thought her sun was doing to my night, it blotted out any semblance of my true self beneath its relentless energy.
"Why, Tia? Why do the ponies of Equestria love you and hate me?"
My sister was taken aback, whether by my words or the sheer envelope of vehemence I wore, I do not know. "Luna, what do you mean? Nopony hates you."
"They despise my night, and so they despise me."
I felt like the hate inside me was burning like a fire, consuming as it looked for an escape from which it could consume all the more.
Celestia's eyes were sad. "What would you have me do, Lu?"
"Give over the day."
She jerked, surprised. "Luna, I can't do that. Even if it were in my power, to what end? Would you keep the day bottled up in favor of your night? What would that do to Equestria, sister?"
"You always get your way."
Inwardly, I cringed, unable to bear the memory of what was coming, but unable to turn away.
"Father always loved you more than me, Tia. I shouldn't be surprised that everypony loves you more."
She took a step forward, her eyes wide and damp. "Luna..."
I could feel it approaching, the moment that filled me with more regret than anything else in my life.
"Well, I don't, Tia."
I felt myself from the outside, mentally mouthing along with the words I knew were coming, my metaphorical tears falling as I watched my sister crumble.
"I hate you."
I know the theory behind dreamwalking. The way magic warps and twists dreams is always different, but there is a pattern. This was the first time that pattern had ever been broken for me. The first time I'd ever been forced to live out my own nightmare in place of somepony else's. Magic is deceptive. It was in the defenseless dream state when the Nightmare first came to me, whispering in my ear. I am still not sure what relation the Nightmare plays with the way these dreams warp and attack, but it is an expert at stripping away your defenses, at finding your innermost weaknesses and laying them bare to tear you apart.
It had a thousand years to learn my secrets. The magic was showing me that weakness now.
I awoke with a cry, tears still streaming down my face, the look of pain and betrayal and the line of every tear on Celestia's face still etched indelibly in my mind. I have lived through more nightmares than I can count on behalf of my citizens, but this was the first time I had ever been affected so. It was the first time I had ever not wanted to go to sleep. For the first time in generations, I felt an intense need to talk to somepony.
Nopony can understand. I closed my eyes, trying to force myself to stop sobbing. To be a dreamwalker is to always be alone, I knew that better than anypony. But the voice in my head returned, the small flicker of peace it brought standing out in my mind like a candle in the black.
And yet... The burden is too great. Everypony needs somepony else.
I jumped, almost spurred to crying out again as I heard the smallest of sounds, a hoof shuffling quietly against the flagstones of my chambers. I turned to face the intruder, coming muzzle to muzzle with my majordomo.
"Your Majesty, I'm sorry—are you all right?"