Rarity watched as Twilight paced back and forth through the waiting room. When they had first arrived, she had tried calming her friend down, but she had resigned herself to the fact that Twilight would just need to fret herself out. Rarity’s head tracked Twilight back and forth as a peculiar pattern repeated itself.

With every tenth trip across the room, Princess Celestia would whisper a firm, “Twilight,” and use her wing to push the younger alicorn into an open seat. Twilight would sit in the chair for usually less than thirty seconds before her hoof began to tap. Before even a minute would be up, Twilight would resume her pacing while muttering about various hospital statistics.

Rarity took another sip of her cup of coffee. She would prefer tea, of course, but the machine out in the hallway had a woefully inadequate selection. As Twilight was ushered back into her seat Rarity looked at the other occupants of the room. Twilight’s parents were obviously worried, but absolutely calm compared to Twilight herself. It was likely reassuring to know that with three genetic relations in the room, there was almost certain to be a compatible donor. Princess Cadance, however, was smiling and chatting away with her parents-in-law.

Obviously, the Princess of Love was confident that her husband would be fine, and from all the statistics that Twilight was spouting off, it seemed that even Twilight thought Shining Armor would be fine. However, Rarity supposed that being infected by a changeling poison was never a light issue.

Every head swiveled to the door as it was pushed open, but a collective sigh rippled through them when they saw that it was just Spike with a tray of sandwiches. Being a private wing of the hospital, the only pony they were expecting to come through the door was one of the doctors.

“Thank you, Spike.” Rarity smiled at the dragon as he handed her a plate with a daffodil sandwich. “How are you doing?”

“Honestly I’m more worried about Twilight than Shining.” Spike looked back towards the pacing alicorn. “How do you think she’ll handle not having magic?”

“Spike, our Twilight is a strong pony. Besides, if she is a match, the doctor said most donors can start using their magic again within a few months. I’m sure with an assistant like you, she will cope just fine.”

“I know, Rarity.” Spike shot her a smile. “I guess we should be more worried about her wearing down her hooves with all her pacing.”

“Yes, well, I just wish Twilight had given us time to talk to the others.”

“They’ll find the note we left at the library. I’m just glad you were visiting when I got the letter about the attack, otherwise Twilight might have dragged me down to the train station without even waiting to leave the note.”

Rarity had not even had the chance to grab a single travel bag. She hoped that nopony would see her in Canterlot without a shred of fashion, but it was a risk she was willing to take for her friend. It would just be nice if she could do something for the pacing pony.

“And I’m glad I’m here as well. I just wish I could actually help. Not even the Princess has been able to calm her down, and it’s not like I have any chance of being a compatible donor.” Rarity looked at the bandage on her foreleg where the nurse had taken a blood sample.

Everypony with the exception of Spike had a similar bandage. Even Princess Celestia had been tested, though the odds of a stranger being a compatible donor were nearly a million to one. Likewise, it was almost certain that Twilight, as a sibling, would be able to help Shining Armor. Still, she thought it was a rather moving sign of support for their friend.

Again everpony looked up when the door open, and again everpony sighed when they saw it was not a doctor. Princess Luna stood by the door for a few moments shuffling her hooves before making her way over to where Celestia was sitting down.

Rarity was able to overhear part of the conversation. She was not eavesdropping. Proper ponies didn’t listen in to private conversations. Rarity just happened to be sitting nearby and just so happened to hear some of what they were saying, not eavesdropping at all.

“Sister, one of us should head back to the castle, it is not as if those accursed doctors are even letting us see Shining Armor.”

“He’s immunocompromised, so it’s a good thing the doctors aren’t letting us see him. But we should be here for him. He is family now after all.”

As Rarity listened she continued to count Twilight’s pacing. She was almost finished with her tenth lap.

“I do not think it is our nephew-in-law you wish to be here for.”

“Twilight needs a-” Celestia cut off as she addressed her student, “Twilight, you should sit down and try to relax.”

Again the door opened, but this time everypony stood up in anticipation as a pony in a white labcoat walked in.

“We have the results of everypony’s blood panel, and I am happy to report good news. We have a match.”

“Finally. When are you going to prep me for the procedure. Is it going to hurt? Of course it is going to hurt, the other doctor already told us that. I just mean, can we get started? Get it over with, that way Shining can get out of the hospital.” Twilight was rambling with hairs out of place in her mane.

Rarity watched as Princess Celestia laid a wing across Twilight’s back, quieting her down and smoothing out her rough mane.

“Actually, I’m afraid you aren’t a compatible donor Princess Sparkle. You actually have zero out of the six required antigens in your blood.”

“What? How is that possible? Statistically speaking I mean? Siblings are almost always at least a four out of six match. All the books I’ve been teleporting in from the library say that. It’s near impossible for me not to have any of the right factors.” Twilight’s eyes grew wide. “It’s not- It’s not because I’m an alicorn now, is it?”

Princess Celestia took a step forward. “Doctor, Twilight’s ascension should not have affected her ability to donate horn marrow to her brother. Twilight received a full medical workup after becoming an alicorn and all of her blood work returned the same as before, minus the additional factors related to her ascension. But you should be able to filter those out.”

“Er- You are correct Princess. It doesn’t have anything to with it. Alicorn or unicorn, either one should be able to donate. Princess Twilight simply doesn’t have the right antigens in her blood to prevent rejection. She likely never did.”

Twilight marched up the doctor until she was right in his face. “How is that possible? Why can’t I donate marrow to my brother?” There were more hairs out of place now.

“I’m not really sure what to say… You are right that, statistically, it is almost unheard of for a blood sibling not to be a match.”

Rarity gasped when she realized what the doctor was hinting at. Spike just looked on in confusion.

“Doctor, you said one of us was a match?” Twilight’s father asked while dragging a handkerchief across his brow.

“Yes!” The doctor’s smile returned. “Mrs. Velvet. You have three out of six of the required antigens, enough to prevent rejection. However, Ms. Rarity, you happen to be a four out of six. Unusual, but not unheard of in ponies who aren’t related, even if the odds of any given pony being a match are small. I suppose in your case we have gotten lucky. It would hasten Mr. Armor’s recovery and reduce the chance that he would end up suffering any long term complications. But as my colleague should have explained to you, the procedure is a painful one with a lengthy recovery. Though, the odds of serious complications on the donors part are all most none.”

Rarity took a deep breath and nodded. She had not offered to be tested for show after all. “Alright. Whatever is best for Shining Armor. I suppose I am ready whenever you are all ready.”

Rarity felt herself being hugged on both sides by Cadance and Mrs. Velvet.

“Thank you so much. I’m so glad Twilight has such a wonderful friend.”

“Hold on a moment!” Everypony turned towards Twilight still standing in the middle of the room. “Are we just going to ignore the fact that for some reason Shining Armor’s own sister is not a compatible donor?”

Twilight’s father’s nervous gulp did not go unnoticed by Rarity, which is why she was unsurprised when Mrs. Velvet spoke up. “Dear do you think we could discuss this in private?”

“No. Everypony here is family or close enough to be family. I want to hear this. Why am I not a compatible donor?”

“I’m afraid that we can explain that honey.” Twilight’s mother took a deep breath. “If you are sure you want to do this here. You see… You’re adopted.”

“I’m what?”

“How come I was never informed about this?” Princess Celestia stepped forward frowning.

“Because frankly Princess, it wasn’t your business.”

“The adoption was not exactly official,” added Twilight’s father.

“You kidnapped me as a filly!”

“No! Twilight sit down. If you are going to make a thing of this you are going to let me and your father explain ourselves. Twilight, sit down right this instant young lady.”

Rarity noticed that everypony in the room seemed to reflexively take their seat.

“You see, there were complications with our little Shiny’s birth, and afterwards, well, we couldn’t have another child,” continued Twilight Velvet.

“We loved Shiny but we had always wanted to have a big family with a lot of foals.” Night Light put a hoof on his wife’s shoulder. “At the very least we thought it would be nice if Shining had a little brother or sister.”

“We started looking into adoption.”

“But before we could make any decision we went on a little camping trip, something to help us think. We left Shining with your uncle for the weekend and went out into the woods outside of Canterlot.”

Rarity noticed Princess Celestia scooch next to Twilight and drape a comforting wing back over her back.

“We were out on a hill staring at the sky, simply enjoying the night, when Night Light spotted a shooting star.”

“I pointed it out and we made a wish.”

“What does any-” Twilight’s words cut off at the glare from her mother.

“Imagine our surprise when the shooting star crash landed at the edge of the clearing.” Despite her glare Twilight Velvet was smiling.

Rarity felt an eyebrow rising in curiosity at the increasingly wide eyed stare of Princess Celestia. Rarity would not have expected the alicorn to react to the story in such a way. However, the stranger thing was Princess Luna. The Princess of the Night kept glancing at the door and every now and then would shuffle a few paces towards it when nopony else was looking.

“When we went to investigate we found a little foal wrapped in swaddling cloth at the center of the burning crater,” said Twilight’s mother.

Rarity blinked. She felt like she should say something but did not know what. She looked at Twilight, but her friend looked the same as always. Rarity sighed. She supposed her friend always had been a bit strange, and one more thing was not going to be the straw that broke the pony's back.

“We don’t know how, but we know that somepony had answered our wish.”

“How is that-” Twilight was once again cut off, but this time by Princess Celestia speaking over her.

“I remember that night.” The words were quiet as the Princess spoke towards the floor.

“What?” Twilight stepped away from her teacher and Rarity watched with concern as some hairs sprung out of place on her friend’s mane.

“I was thinking about Luna, and how much I missed her. I was very lonely back then. I had weathered nearly a thousand years on my own and was tired. It was back before I had found Cadance. But, I saw that same shooting star, I think. The timing seems right. I wished on it as well. I wanted… As I wished on it, I saw it crash into the forest. I thought it an ill omen at the time. I sent some guard ponies out to make sure it hadn’t hit anypony, but they reported just an empty clearing with a smoldering crater.”

“After we pulled our Twiley out of the crater we decided it was best to leave. We did not want to have to answer any questions,” Night Light clarified.

“But- That doesn’t really explain where I came from. Ponies don’t just fall from the sky in shooting stars.”

Rarty’s head swiveled at a heavy sigh. She had been so absorbed in the tale she had forgotten all about Princess Luna.

“I think I can answer that,” Luna muttered.

As every eye turned towards Luna, Rarity noticed Twilight step towards the center of the room. The poor dear was a complete mess, and understandably so. Rarity, of all ponies present, understood how such news could be unnerving and stepped next to her friend. She tried to lean into Twilight as a show of support, but as Luna began talking Twilight resumed her pacing, only now with a frantic edge.

“Now, I want you all to keep in mind that the last thousand years that I spent trapped in the moon are hazy. In my madness most of the details became jumbled, but I was aware of what was happening in Equestria, after a fashion. And even trapped, I could still exert some of my influence.” Luna seemed to be looking anywhere but at the ponies she was speaking to.

“As Nightmare Moon I was filled with a great deal of anger. However, even then, I have always had a particular fondness for petitioners, and what is a pony wishing upon a shooting star but a petitioner. I had three ponies all baring their souls to me, wishing on the same star, and even with all of my hatred, part of me still loved my sister. When three wishes can be granted with a single simple act, well it was hard not to do something.”

“I don’t understand. You, what, made me out of magic?” Twilight was standing perfectly still. Rarity could not help but feel that it was a bad sign.

“I suspect so. If you are asking me how though, I cannot answer. I do not know of any magics that could accomplish such a thing as making a pony. However, as Nightmare Moon I was capable of much that I cannot do now. All I know is that I heard a wish and I granted said wish.”

In a bright flash of lavender magic, Twilight disappeared.

“Oh dear.” Rarity covered her mouth with a hoof.

“Rarity, do you think you could go be with Twilight. I think she needed somepony right now, but I’m worried she might not want to see me right now.” Princess Celestia kept glancing at Princess Luna as she spoke.

“I would love to be there for Twilight, but I don’t even know where she went.”

“Let me take care of that.” With the Princess’s words, Rarity was bathed in a golden light.

Rarity looked around, not quite sure where she was. It seemed to be some sort of tower, perhaps an observatory. It looked like it had not seen any use in quite some time, and with only the illumination of moonlight shining through the windows, Rarity felt a shudder running down her spine. She shook her hoof trying to shake some of the dust off of her fetlock as she stepped across the floor.

Then she saw the bed against the wall with a lavender bedsheet marked with Twilight's cutie mark. Rarity realized she must be in Twilight’s old room in the castle. Twilight never really talked much about her time in Canterlot. Rarity wondered why.

Her head craned around as she took it all in. The room was absolutely huge and resplendent with works of art. Rarity never would have guessed her friend had lived in such comfort from the homely tree that Twilight now seemed satisfied with.

“I hadn’t realized her family was so wealthy. Or perhaps this was all a gift from Princess Celestia.”

Rarity shook her head. She had more important concerns at the moment. If Princess Celestia had sent her, Twilight must be somewhere nearby. Her eyes followed the spiraling staircase to the upper levels and figured they were as a good of a place as any to start.

When Rarity eventually reached the top level she found Twilight sitting on the balcony staring at the stars.

“Twilight?” Rarity spoke softly, not wanting to startle the mare.

Her friend whirled around and embraced Rarity in a hug that caused her to wheeze for breath.

“Oh Rarity, I don’t even know what to think right now.”

“Well… What about Spike?”

“What do you mean, what about Spike?”

“I’m sure that you are confused about your brother, and parents, and the other Princesses right now, but Spike seems like he might be easier to deal with.”

“Nothing has changed about Spike. He’s still like a-” Twilight cut off as she started to smile and wiped away a tear. “I see what you did there. OK, I guess Shining is still my brother, and my parents are still my parents. That doesn’t mean I’m not mad at them for keeping this from me though.”

“And I think you have every right to be upset. Just don’t let that ruin your relationship.”

“I- I’ll try. I don’t think I can just adapt to this overnight. It’s a lot to swallow.” Twilight laughed. “I find out that not only am I adopted, but I’m not even a real pony.”

“Darling, why would you say something like that?”

“You heard what Luna said. I’m some sort of magical construct.”

“That is not at all what I heard Twilight, and if that is what you think you heard, you need your ears checked.” Rarity used her magic to tug on Twilight’s left ear. “What I heard is that two ponies wished for a foal and a third wished for a release from her loneliness. That wish was granted and a daughter and friend fell to Equestria. Nowhere in there did I hear anything about you being some sort of construct.”

“But-”

“No buts. You are Twilight Sparkle, personal student to Princess Celestia and now a princess in her own right. You are the sister of Shining Armor and Spike the dragon. You are the daughter of Twilight Velvet and Night Light. You are my friend. Maybe your origins are a bit unorthodox, but I personally would not want to associate with anypony who would judge you for that.”

Twilight held back a sniffle. “Thanks, Rarity.”

“I will admit that there are a lot of questions. But I don’t know if any of them can’t wait to be answered. Right now your family is worried about you.”

The two sat in silence for awhile. Rarity knew that Twilight needed time to process everything and was more than willing to give her friend that time.

“What about,” Twilight continued in a murmur, “What about the Princess?”

“Princess Celestia? I think she is just as worried about you. She was the one who sent me here.”

Twilight nodded her head in what Rarity supposed was understanding. “I suppose we should get back then.”

“Twilight… If you ever want to talk about it, I know what it feels like. Finding out you are adopted I mean.”

“Rarity, you’re adopted?” Twilight looked at her in surprise.

Rarity nodded her head. “I am. I’m terribly sorry for not mentioning it earlier. It’s nothing I am ashamed of, but until this year Sweetie Belle didn’t know, and so it was something I tried to avoid talking about. More habit than anything else I suppose.”

“You told Sweetie Belle? How did she take it?”

“Not,” Rarity paused for a moment, “Not well I am afraid. You may have noticed that our relationship has been a bit strained. However, I think she is adjusting and realizing it doesn’t really change anything. The fact that I am adopted and she’s not is really just meaningless. I know it is not the same thing as being some sort of star foal, but-”

“Thank you for sharing that with me.” Twilight leaned in and hugged Rarity. “It helps a lot knowing that. I mean. I know everything we talked about, but part of me just can’t help but feel like something is different about me. That I’m nothing but a lie. However, you’re adopted, and there is nothing different about you. You’re still the same Rarity.”

“And you are still the same Twilight.”

“We should probably get back to the others.” Suddenly a dozen hairs which had been smoothed down popped back up out of Twilight’s mane. “Shining! I completely forgot about him.”

“It will be OK, Twilight. Once you teleport us back, the doctors can start preparing things for the transplant.”

The two hugged again as lavender magic carried them back to the hospital waiting room. Rarity noticed that Princess Celestia was smiling, but everypony else seemed nervous.

“Sorry everypony that I freaked out. I still have a lot of questions, and mom, dad, we are going to need to talk more later, but I think I’m OK.”

Rarity gracefully stepped aside, as Twilight was mobbed by her parents, Cadance and Spike. They were all making comments of support and hugging the flustered alicorn. Rarity looked up at the motionless Princess Celestia.

“You aren’t going to join in?”

“I’m sure Twilight would rather be with her friends and family right now. She just received very emotional news after all.”

“Excuse me if I may be so bold, Princess, but was it not partly your wish as well?”

Rarity watched as the Princess’s eyes widened and then shrunk. The alicorn’s smile seemed to grow as she moved forward and swept the entire mob of ponies up in a massive wing hug.

Eventually the heart warming sight was broken up by a cough from the doctor. “Excuse me, but it would be best if we got Ms. Rarity into prep as soon as possible. Shining Armor should be safe in isolation, but it is best if we avoid delays.”

Then it was Rarity who found herself in a pile of hug that was only broken by another cough from the doctor.

As Rarity made her way to the door, she stopped when Spike tugged on her tail.

“Rarity, I know we’ve already all said it, but thanks a lot for helping Shining Armor. If you want, while your magic is recovering, I can help you out. You know, help you with doing things that might be hard without your magic.”

Rarity smiled at the dragon. Spike could be so cute sometimes. “I think I would like that very much. I have a feeling that it might be quite a struggle, if not for your help, when I get back home.”

Exiting the door Rarity heard Twilight saying one last thing. “By the way, Princess Luna. I don’t think I am going to be calling you mom.” And as the door closed Rarity could just make out the sound of a pony spitting out their drink.

Author's Notes:

IMPORTANT
It is a common misconception (that my story helps to propagate) that bone marrow donation is a painful or serious procedure. While that use to be true, now a days it is basically a blood transfusion (assuming you are donating to an adult). So don't hesitate to donate bone marrow.
End Important stuff

So originally Shining Armor was actually a character here, but that was not working out so I cut him and most of the stuff with Cadance.

I originally had an idea for a very different story with an almost identical basic premise, but I can't for the life of me imagine what it was.

Also, I almost started writing a SoL sequel about Twilight recovering from giving bone marrow without her magic when I realized it wasn't actually Twilight who donated the marrow.

I had no idea what to tag this as. I don't really feel that it is Slice of Life, but none of the other tag come even close.

EDIT: Just posted a Twilight Sadfic Not an Adult. Nopony dies or anything. It just looks at some of the issues Twilight deals with.