I just watched a MLP fan video from 2015 called Remembrance, and I had to write a story set in a similar universe.

Celestia's Perspective

Being immortal, Celestia knew that loss of anypony was an inevitability. She'd lost many Ponies who had meant a great deal to her, and had for a millennium lost the one true family member she had left. Loss was no stranger to the immortal alabaster Alicorn.

That never made the passing of somepony any less hard. Especially when that Pony was her once faithful student and former Alicorn Twilight Sparkle.

The bedchamber where the aging mare lay was surrounded by all those Twilight held dear to her. Not only was Celestia there, but so was her sister Luna as well as her husband Jethro Bethridge. Celestia's wing was on his back, trying to comfort the ageless human/Alicorn hybrid. Despite the four hundred years he'd been married to Celestia, Luna, Twilight, Zecora and the others of the herd he'd managed to form despite his early fears, loss seemed to come especially hard to him. Her husband's eyes were bloodshot with tears as he gently clung to Twilight's hoof.

Twilight's purple eyes were also full of tears as she weakly reached out to her husband. "Jethro…my dear stallion…please don't cry."

Celestia's wing tightened around Jethro as he put Twilight's hoof to his cheek. "How…can I not?" he said with a trembling voice that broke Celestia's heart to hear. "You're…the last one. Everyone else…"

"They're in Elysium, waiting for me," Twilight said, smiling through her tears. "Jethro, it's time for me to go. Please…remember all of the good times we've all spent together."

Luna came to Jethro's other side, placing her own wing on his back as well. She looked over at Celestia, and the solar Princess knew the look on her face almost instantly. It had been similar to the one Celestia had seen on her own face many times after a loss. But for Jethro, even though he'd experienced the loss of only a handful when compared to the number Celestia had lost, the Princess knew each loss tore at his soul much more deeply than anything Celestia had gone through. Even now, Celestia fought to keep the tears in her own eyes from falling.

On the other side of the bed, Sunset Shimmer, the newest Alicorn Princess of Friendship as well as a taller Spike, were kneeling and trying their hardest not to shed tears as well. Spike had an arm around the bacon maned Alicorn. Empress Cadance and Princess Flurry Heart both stood nearby, Flurry openly not hiding her own tears as she buried her face into Cadance's barrel.

Twilight turned to Jethro. "Help me sit up, please," she said softly. Jethro gently fluffed some of the pillows to make her more comfortable then helped her to a better sitting position. Twilight looked over the gathering, smiling at them all. "I know I don't have much time left, so I wanted to say something to everyone here."

She turned first to Cadance. "Cadance…you were the best foalsitter a little filly could ask for. But you were much more to me than that. You were like my older sister, the one I never knew I wanted. And when you eventually married my brother…you even became my older sister. I was so happy when you married my brother, because now I had a real sister I could spend time with. And then when you and Shining had Flurry…I couldn't have been happier than to be an aunt. I love you, Cadance."

Cadance took a deep breath, and nodded. "I love you too, Twilight." She lowered herself, then smiled. "One more time?"

Twilight chuckled. "You'll forgive me if I don't stand."

With that, Cadance began dancing up and down, and Twilight nodded her head in beat. "Sunshine, sunshine, ladybugs awake. Clap your hooves and do a little shake," the two said in unison.

Twilight smiled, then turned to Flurry. "Flurry…"

"Auntie Twilight…" Flurry said with a trembling voice.

"Shhh…" Twilight said softly, "Flurry Heart, you were my first niece. I love you, even if you were a pain in the ass during foalhood." That got a few chuckles from everyone in the room, even Flurry. "It was a privilege and an honor to watch you grow up into the lovely mare I see before me today. I'm sure you've broken plenty of hearts, and that's just today."

Celestia smirked. Twilight had been influenced by the now passed Scarlet Dusk. She was proud that Twilight had loosened up over the years thanks to her and Jethro's influence. Flurry's eyes were full of tears as she rushed over and hugged the frail purple mare. "Auntie! Don't go, please!"

Twilight smiled sadly and put her free hoof around Flurry's back. "I'm sorry, Flurry…but my time is here. I've had many wonderful years with everyone in this room. More years than anypony has ever enjoyed before. Please remember those times fondly, not with sadness. I love you, Flurry Heart."

"I…love you too, Auntie Twilight."

Flurry finally released Twilight, who then turned to Sunset Shimmer. "Sunset…our first meeting was, to put it bluntly, a complete shit show. I won't deny I found it hard to forgive you after everything you did, but I'm proud to call you my friend and my eventual successor. You've done so much for Equestria. More than I ever could have done."

Sunset's eyes glistened with tears. "Twilight…I'll miss you so much…"

Twilight smiled kindly at the young looking Alicorn. "Keep the idea of friendship alive and well in the world, my friend. I love you."

"I will," Sunset said. "I love you too."

She nodded, then turned to Spike. "Spike. My son. My very first son."

The now adult dragon, who was a head taller than anyone else in the room, came to the side of the bed and took her hoof. "Twi…mom…"

"You were always there for me, even if I initially never realized it and took you for granted," Twilight said softly. "You were my very first friend, my number one assistant for many years, and a son I can be immensely proud of. You've done so much for Equestria. I love you."

"I love you too, Mom," Spike whispered, kissing her hoof. "I'll miss you so much."

Twilight then turned to Luna. "Luna…we might not have started off very close, but over these past few centuries, I'm proud to have grown to love you as a close friend. All the times we've spent together, all the nights we've looked up into the sky and wondered what was beyond will be memories I cherish forever. I love you, Luna."

Luna wiped a small tear with her wing, and smiled. "As shall I, my friend. As shall I. I will miss those nightly sessions with you there. I love you, too."

Twilight nodded, then turned to Celestia. Celestia couldn't help it: she smiled. The look on Twilight's expression was one of pure love for a mentor, a mother figure, and a friend. "Celestia," she said, and Celestia could hear the aging Unicorn's voice growing tired, "You were like a second mother to me. You taught me so much about magic, and when you sent me to Ponyville to learn about friendship, my appreciation and love for you only grew. You were my teacher, and now I'm proud to have been allowed to call you my friend. I love you, Celestia."

Celestia leaned down, nuzzling Twilight's cheek affectionately. "I love you too, my faithful student, and my friend. I will miss you."

Twilight smiled, then finally turned to Jethro. "Jethro…"

Jethro was kneeling in front of the bed, unable to look Twilight in the eyes. "Twi…I…"

"Please…look at me," she begged. When Jethro finally raised his head to meet her eyes, she gave him her most radiant smile. "Jethro Bethridge, don't let this day go sour. I know how much you've lost. Just know that our time together was a joy to me. I am proud to have been married to a man like you. No time was ever wasted between the two of us." For the last time, her horn glowed and she pulled him close. Jethro finished the motion by planting his lips against the ageing mare's lips for the last time. "I love you so much, Jethro Bethridge."

"I…love you so very much, Twilight Sparkle," Jethro said, kissing her forehead, then cheek, then lips, and then finally releasing her.

Twilight looked around the room at all the gathered individuals. "This…is farewell, everyone. But not a permanent goodbye. I know, one day, my friends and I will see you all once more. We will be together one day…in paradise…"

And with that, Celestia watched as Twilight took her final breath.

Luna's Perspective

Twilight's memorial service was attended by the many Ponies, Griffons, Dragons, Lycans, Hippogriffs, Dark Fae, Yaks and the other species who's lives she had touched thanks to her actions as the first Princess of Friendship. The memorial lasted from morning until night. Jethro led the service, reading many touching words from his religious text the Bible. Many others read from the Book of Harmony and Friendship, written by Twilight and her friends. Still others spoke of their personal experiences with Twilight.

As the night closed around the gathered assembly, Princess Sunset, the current Princess of Friendship, gave the closing speech, where she told of her own experience with Twilight and the passing of the torch. Luna listened to everything that had been said, taking in everything. She sat beside her husband, one of her wings around his shoulders, while Celestia sat on Jethro's other side, mirroring Luna's actions.

Jethro had taken Twilight's death the hardest out of everyone present, it seemed to Luna. He'd lost the mortal members of his herd over the past five years, and it hadn't been easy for him. Luna and Celestia had tried to comfort him many nights, but it felt like a losing battle. Luna was afraid that he'd do what Twilight had done two hundred years ago, sacrificing her wings to bring her friends back from the brink of death.

Twilight's sacrifice had given them two hundred extra years with the Bearers of Harmony as well as Zecora and Scarlet, and for a time it had eased Jethro's aching heart. But then the two hundred years had passed, and the first began to pass into the next life. With every death, Jethro smiled less and less until it became harder for him to smile at all.

Not even the love poured out on him by Celestia and Luna seemed to help. He kept apologizing for it, but nothing seemed to help his own mood.

And so, Luna found herself lying in the bedchamber that she shared with her sister and her husband, all three lying and facing the ceiling. There was silence between all three of them. No words seemed appropriate. Luna wanted to see her husband smile at her once more, just like he had on their very first date. She wouldn't even have cared if he'd smiled at her sister and fellow herd mate Celestia. All that mattered was that he smile again.

To her surprise, as midnight rolled around, Jethro took a deep breath, and finally said, "It's finally over…"

Luna turned to face her human lover. "Dearest?" she asked.

Celestia was immediately awake and facing him as well. "What's over?"

He slowly sat up, reaching out with his magic to slowly turn on the light above their bed. It shone with the shimmering light of the moon, illuminating his features. Luna's heart broke to see the tear-stained cheeks and bloodshot eyes of her husband, and she immediately pressed herself against him. Celestia did the same. She was rewarded by his arm and wing around her, pulling her and Celestia closer to him. "Cellie, Lulu…" he said hesitantly, finally using the pet names they'd both loved to hear him call them after so many years, "these past five years have been hard…very hard for me. But…they've been hard on you too. And I didn't help, did I?"

Celestia pressed herself against Jethro. "Love, you've never lost anypony for centuries…"

"But it wasn't fair of me to shut you two out of my life because of that," he said. "Four hundred years later, and I'm still failing at being a good husband."

Luna immediately sat up straighter, pushing him down and straddling him, her front hooves on his shoulders. "No!" she shouted, angry and sorrowful tears forming in her eyes. "You did not fail us! Never think that, dearest! My sister and I made a promise to you! A promise to remain by your side through the good times and the bad!"

Celestia moved closer, leaning her cheek against Jethro's chest. "Your heart has been filled with nothing but grief over these past five years, it's understandable that you would find it hard to find a way to cope with loss around every corner," she said tenderly.

"Maybe…but I still should have let the two of you in," he whispered, looking away. "And not just you. Sunset Shimmer, Spike, Flurry Heart and Cadance. I should have let them all in. They're my family too, and for five years, I shut them all out."

"We forgive you," Celestia said. "And I know they do too."

"Tomorrow, would you like to speak to them?" Luna asked, lying down on top of Jethro and snuggling close. She was once more rewarded by a wing and arm around her body.

"Yes…yes I think I would," he said. "I am…so tired of running from this."

Luna's heart leapt for joy as she snuggled closer. Celestia also pressed herself against Jethro. "My dearest Jethro," Celestia whispered softly, "we are both here for you. Your family is here for you. We will mourn and heal together. Cross my heart, hope to fly, stick a cupcake in my eye."

Jethro snorted. "Foreeever," he said, in his imitation of Pinkie Pie. "Thank you…both of you." The light dimmed as he pulled both women in for a kiss. "I'm ready…"

Luna's eyes fluttered closed, and for the first time in five years, she felt the hope within her rising. Her Jethro was coming back to them...