And there is a fragile beauty in Luna falling apart.
Celestia watches from the sidelines, despairing in her hopelessness. Luna drifts and wanders in her night, and each day the moon falls a little later and rises a little earlier. Celestia does as she is told and raises the sun every morning and pulls it down every evening. She's constantly jumping at shadows, because Luna now follows her footsteps as it reaches dusk. Whenever Celestia looks back, Luna turns her head to the sky, meaningful.
Celestia does as she's told.
The citizens of Canterlot and beyond come to her with pleas – it is spring, and the sun is needed to grow crops and flowers. They have been through three months of short days, and Luna refuses to give it up. Celestia dips her head to each Pony in turn. "I will do something to fix it. I promise." She had a duty to her people.
So did Luna.
Luna brushes beside her at four. Celestia looks back. "It's still mid-afternoon." Her whisper echoes in the large room.
Celestia is pinned into place with Luna's sharp gaze. She's gotten taller. "Lower the sun." She answers, and her voice is no louder, but carries a heavier presence.
The elder mare frets in place, shifting her weight from hoof to hoof, before lowering her head. Celestia can only do as she is told. The sun is lowered.
It doesn't rise again.
Luna became like the night, her pelt deepening from its sunset purple to a dark, midnight blue. Around her, the ponies despair. They come in droves, from far and wide, begging now, down on their forelegs. Celestia tries not to cry as she whispers promises to them in the dark. She'll fix it – she will. She has a duty.
Luna stands on the highest peak of the castle in Canterlot, head turned to the moon, as if they engaged in an intimate conversation.
Celestia swallows everything, and forces it down into her hooves and then further still. Pegasi hover anxiously around her as she departs, walking up the stairs to where Luna stands. It is the longer route, but Celestia takes that time to steel herself for what she will face. This is her sister. This is the only pony Celestia loves above all others.
And watching her become this thing has destroyed Celestia as surely as it has destroyed Luna.
Celestia stands on the edge of the roof. Luna does not acknowledge her presence, but speaks: "Isn't it lovely, sister?" Her voice curls through the air like poisoned smoke.
"It is beautiful." Celestia agrees, for she is not a liar. Luna's nights have always been stunning – the curl of dark purple through the sprinkling of bright stars never fails to impress her. Where Luna creates all this magic, Celestia raises the sky, same as everyday: if clouds come between it, that is not her doing. Luna puts in so much work, and Celestia knows she deserves the recognition. Is this what she is now forcing? "I have never said otherwise."
Luna snorts. "And have they ever said it to begin with?" Again, her head doesn't shift, but her eyes flick down to the crowd of ponies in the square.
"Of course, Luna." Celestia starts out, tone pleading, and she steps forward.
Luna snaps back her way, turning on her hinds. "Do not try to placate me." She snarls, muzzle curled back, teeth bared.
Celestia flinches. "Please, Luna. They cannot survive like this." She casts a look down to the ground where her – their – people wait.
"They should have thought of that." Luna says, and Celestia watches her forelegs work the roof, as if she is unable to stand still. "They created this – they forced me to do this! And now they will love me!" There is desperation in her voice, a desire to just be appreciated.
Celestia's heart breaks as she stands there. "Luna, we can work something out." She pleads, coming forward now to stand beside Luna.
There is a moment where Luna pauses. She stops and turns so that their horns brush. "I'm sorry, sister." Luna sounds honestly apologetic. "But there's nothing to be done." Luna brushes past her sister, trot breaking to a canter and then into flight.
Celestia watches as she flies away from Canterlot, leaving them all wreathed in her eternal night.