Celestia pours through a book on empathy and communication related magics. There are dark lines under her eyes, and her mane is limp. Her heart feels like it's going to burst from sleep deprivation-- and hope. She then turns to her magiometric calculations, and starts to work it out. After she works it out, she stands, legs wobbly, but with a lopsidedly hopeful smile on her face.
'I really need to get some sleep, but I need to try this out! I may finally be able to communicate with my sister..!' she takes a deep breath in excitement.
After a very quick flight to Luna's room, she knocks a particular way: the way she always does. She learned long ago that her baby sister needed lots of routine and predictability. What this amounted to was, if she didn't do things a particular way, come at a certain time, stay for a certain length, her time with Luna would not be pleasant.
'The best doctors from all over Equestria have seen Luna. They have no idea what makes her this way, so slow to develop and hard to teach...' She gives a scowl, thinking about Small Good-blood, the Gryphon doctor who had named Luna's condition. 'My sister isn't alone. I spend as much time as I can with her, and I am about to communicate with her in a way that nopony ever has before!'
Luna's blue magic opens the door. There she is, in her corner of the room. Huddled in her blankets, the blue alicorn rocks from side to side, a smile on her face. Did that smile ever change? Celestia walks over, and sits near to her, but not too near. She activates the spell.
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"Aaah?" Luna makes a sound, mouth wavery, but still the same smile. Celestia receives a note of confusion, then quick, bright-flaring recognition. <>
<> Celestia gives a proud smile, and Luna gives a squee at the sense of pride and sisterly love coming from her.
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Their hearts were united in joy.
Luna rolls around, fluttering her wings merrily against her wide open floor. The door starts to open, and Luna stops rolling, and gets back in her corner, under her blanket den. Celestia glares at the guard who opened it.
"I'm sorry, your highness. You are needed in the throne room."
"Alright. Let me say goodbye to Luna, and I'll be coming."
"Yes, your highness," he says as he bows and walks out.
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<<'Kay!>>
With that, Luna settles into her magic dampening bracers and waits for her regular caregiver. However, unbeknownst to her, things were ahoof that would prevent her from coming. This wasn't a good thing.
As Celestia walks out, not even having closed the door, a young stallion runs up with a worried look on his face. He gasps and pants breathlessly as he bows. She recognizes him as the son of the mare who usually watches Luna.
"I'm sorry, Princess. My mother is badly ill. She told me to come here and watch Princess Luna, with your leave."
"Very well. You know that she needs routine, and it's often best to let her do as she wants?"
He nods, and she thanks him, and says he'll be payed. She heads to the throne room, entirely missing his smirk. He walks in.
When Celestia returns, the same smile is still on Luna's face. However, the vast majority of Luna is quite hidden under her mass of blankets in the corner.
"Princess Luna's been like that for most of the day," her young watcher says.
"She's not used to you yet. She'll need a little time."
Celestia notices the blankets quivering madly, and tries to link with Luna again. Luna's mind, however, is a mass of fear and torment that almost immediately drives her out. Celestia rushes to her, and Luna lets out a moan. Celestia looks back at the stallion, a bemused look on her face.
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Luna lets out an eeh, shaking all the more. Her horn glows brightly, and Celestia dodges a lightning bolt. She rolls on her back in an agonized fashion, her horn letting out sparks. Celestia backs away, and takes the stallion out of the room, putting Luna's favourite blanket within her reach.
"What happened today?"
"Nothing. She sat in her corner, rolled, flapped her wings, and stayed away from me. I may have hummed and talked to myself a little to pass the time, but that was it."
She gives him a hard, frankly concerned look, deciding to ask his mother about him.
"Maybe you should talk less. Set up a den of your own."
"Thank you, Princess. I'll be sure to take your advice."
"And maybe I should talk to her less. Well, why don't you get yourself some lunch? I'll watch her."
She gives a polite smile, re-entering the room to see if Luna had been soothed. She had, and was now rolled in her blanket like a burrito. There was a heavy quilt completing her den.
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Luna levitates the quilt up. There, Celestia can see another blanket, unused.
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Luna jerks back, as if in shock. She shies away from Celestia, and holds the blanket lower. Celestia nods, wraps the blanket around herself, and crawls under. She is at the edge of the quilt, and stays there. Slowly, Luna inches her way towards Celestia, and presses her side against her sister's.
The next morning, after Celestia left, the Stallion continued his abuse. He softly stroked her blank flank and her shapely bum, as Luna flinched and quivered at the unwanted, even unintentionally painful touches. 'It's almost like she understands what I intend,' he thought, giving a shudder of his own at his personal garden tending. 'Good thing the cute little retard doesn't understand, and can't communicate.'
The next day, he let her see what he did to himself while he touched her. The day after that, he touched her mare parts for the first time. Day three, he started getting her used to being immobilised.
The next day, Luna only thought-communicated with Celestia in the morning. The day after that, she couldn't do it at all. Day three, she had a screaming and crying meltdown that Celestia was hard pressed to soothe.
Day four, Celestia asked his mother about him, and learned that she hadn't sent him at all. She learned that no one in his family really trusted him. She learned that he was dishonest, and her heart nearly stopped when she learned that he was an offender. It was too late. The now monstrous seeming stallion had already begun the unthinkable.
Day four, Luna descends into the depths of her mind, screaming for help. She is shocked to receive a response.
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<> Luna's mental voice is filled with hope.
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Luna now has a defence mechanism for when she's being abused. Go see friend! Friend shelters her, protects her, and teaches her spell to protect herself. This leads to Luna feeling better, because Luna has an escape for when the light, soft touches become too much. But friend sees danger coming...
"You know, your sister would probably thank me if I slipped..." He says, stroking her body with the flat of a wicked looking, sharp knife. He has no idea how wrong he is, or the fact that said sister is now on her way.
Luna lets out a pained squeal as his excited state distracts him and his knife nicks her skin. He grabs her mane with this teeth, pulling on it as she squeals in pain.
<> Friend commands as he places the knife to her horn and begins to scrape.
She starts to cast, the magic holding off the blade temporarily. He slowly rubs her body in the way he knows will create the most shrieks, but it's almost like she isn't feeling him at the moment. She lets another loud "Eeeeh!" out, her horn glowing all the fiercer. Her fear and pain inundate the spell, turning it black as she fires it, thoroughly retreating, forcing her friend to the forefront. Her friend's mind is changed by the dark spell's residue, and she begins to be filled with absolute rage and lust for blood. Her roar shakes the castle, and the evil stallion is flung from Luna's borrowed, blackening body.
Celestia races into Luna's room and takes it all in. The way a black, blank flanked alicorn uses the hapless body of the evil pony, and way he's still dangling, not fully receded. The way the Alicorn glares into Celestia's eyes as Luna never could.
"Luna is mine to protect, now. She needs solitude and calmness, so she can learn without fear of evil ponies like that," she says, grinding her hoof against the now sorely injured stallion.
"Please, please, just give me back my sister," Celestia weeps.
"No! You let this happen! You don't deserve my Luna!"
"She's my Luna too!"
The black mare gives a roar, and starts to fire spells. Celestia dodges and backs away, weeping and groaning, all the while thinking, 'This is my worst nightmare.' As she banishes the black thing her Luna's become, she screams loudly with her telepathic spell. <>
The next morning when she goes to raise the sun, she steps to the podium, eyes visibly puffy as she speaks. She declares the Celebration of the Summer Sun to be an occasion to remember lost loved ones. She raises the sun, flies to Luna's room, crawls into her den, and weeps.
