The Ultimate Sacrifice
Twilight knew that possessing the magic of all three princesses alongside her own wouldn't be easy, but she still wasn't prepared for how difficult it truly was, especially when fighting against someone as powerful as Lord Tirek. He was in no way, shape, or form, phased by Twilight's power, with all the power he had absorbed from unicorns across Equestria.
He'd fired several shots at her, but she'd dodged every last one. However, that only made matters worse, as it meant his flaming breath would instead set fire to Canterlot. Panic spread among its citizens, several fleeing their homes and the town itself as the terror only continued.
Twilight was nearly ready to surrender as she grew more exhausted with each shot she fired. He was just too strong for her to handle, and she didn't have the elements with her, or those who beared them. By this point, hardly any hope remained. She truly believed that not just Canterlot, but all of Equestria, was indeed doomed. If she couldn't defeat him with the power she possessed, nopony could.
Collapsing to the ground, she shouted breathlessly, "Alright! You win! Go ahead and burn this place to the ground, for I cannot test your power..."
She began to fade from consciousness, when she saw a familiar-looking alicorn land in front of her. The voice thereafter was just as familiar.
It was that of Celestia.
"No!" she shouted, flying upwards to face Tirek eye-to-eye. "You will not hurt her, nor will you do any more harm to Equestria! As ruler of this land, it is my duty to protect my subjects! And now, I must protect them from you!"
The only response from him was a loud, deafening laugh. Celestia gave him one last glare before using her horn to absorb her magic from Twilight, who was now fully unconscious, having passed out from exhaustion.
She tried to fire at him, but he knocked her back with his own power. For the first time since her niece's wedding, she felt completely weak. He truly was too powerful. Her knees shook as she tried to get up, only to fall right back down. She lost hope as Tirek cackled again, when she suddenly heard her sister from a few feet away.
"Sister!" she called, running faster than anypony had done during their escape from Canterlot.
"Sister, are you alright?!"
Celestia struggled to stay awake. Her eyes fluttered as she spoke, her voice shaky and weak. "Luna...there's nothing else we can do. We...we have to surrender."
Following this statement, she blacked out completely.
Luna's eyes widened in a state of pure shock, as she never thought Celestia would suggest such a thing. Looking around frantically, she tried to find another way. Surely, she believed, there must've been someone or something that could change such an outcome. After a short minute, however, she knew exactly what to do.
The only problem?
It was going to hurt the citizens of Equestria, her sister included, much more than it was going to hurt her.
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Her whole body shaking vigorously, Luna was the next to confront Tirek directly. She refused to absorb her magic, however; what she was about to do didn't require it.
"I now understand that there is nothing we can do to defeat you. But, I am willing to make you an offer, if you are willing to leave Equestria...permanently."
Tirek nodded patiently. "Go on."
"I will offer you my life, only if you vow to depart from this land, and never return."
Tirek's stern expression turned into a sinister grin. "Deal."
Tears formed in Luna's eyes almost immediately after he agreed to her offer. Tirek laughed at her saddened expression, but right after, looked at her with visible confusion. "Wait. You're immortal. How am I supposed to-"
Luna cut him off, putting a hoof to his mouth. "Only my soul is immortal. I am not immortal as a whole. You have the power to take it from me. So, take it, and I am no more."
Tirek's sinister grin returned, and he raised his hand up in front of her muzzle. "Any last words?" he growled.
She felt the tears returning, and only this time did they flow freely from her eyes. Looking down at the ground, she noticed Celestia regaining consciousness. "I'm so sorry, sister," she whispered, voice quivering. After that, before she could even blink, Tirek began to absorb the immortal soul within her.
All that she could get out was a short, anguished cry, before her eyes rolled back in her head and she started losing herself entirely. Down on the ground, Celestia gathered enough strength to get up, and almost immediately realized what was going on. Astonished, she shouted the only word she could think of.
"NO!"
Her fear turned into rage. This monster had gone far enough, but the fact that he was hurting her sister pushed her far beyond her breaking point. In a fit of pure fury, she shot at him with her magic, using every last ounce of her energy. Thankfully, it was enough to knock him back, but not enough to kill him. He laid on the ground, finally reaching his weakened state. Luna flew backwards and hit the ground with a surprisingly loud thud. Celestia sprinted to her not even three seconds after she hit it.
"Oh, no..." she whispered desperately. "Oh, goodness, no..."
Luna was barely alive. Tirek hadn't absorbed her completely, but it was enough for her to be on the verge of death. Celestia didn't even try to hide the tears brimming in her eyes. Without hesitation, she placed a hoof on her sister's, allowing those same tears to flow.
"I...I'm so sorry," she whispered. "If only I was strong enough...then, maybe...this wouldn't have happened to you."
Luna used what was left of her strength to softly smile at Celestia, and spoke with a pained whisper. "I had no other choice. I couldn't just...let you surrender. I'd rather die, than watch you suffer. I had to do that on the moon...I wasn't about to do it again."
Following her last word, she coughed uncontrollably, but was able to lift one wing to pull Celestia towards her. She whispered her last words directly into her ear:
"I love you, sister..."
One last trembling breath escaped her mouth, before she finally accepted her fate.
Celestia stared in disbelief at the heartbreaking sight before her. Just then, Tirek arose.
"Ah," he bellowed. "I see she's finally completed her offer. I made a vow to never return if she gave me her life. So, I shall never return to this forsaken land. However, Celestia, just know that the peace of your precious kingdom came at a great cost, and you will remember this fateful night for the rest of your days. Wouldn't it have just been easier to surrender?"
He left Equestria permanently, laughing maniacally. Celestia bowed her head, letting her emotions overpower her.
"Yes," she sobbed. "It would have."
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Luna's funeral was by far the most heartbreaking funeral Celestia had ever attended. Her little sister, her blood, her family, gone.
She had asked Twilight to read her eulogy, as she couldn't have done so without breaking down. However, she broke down anyway, being reduced from a regal ruler to a traumatized, sobbing alicorn in a matter of seconds. And she did so before Twilight even started reading. When she did, it only made matters worse.
"This eulogy was written by Princess Celestia, but I've been asked to read it on her behalf." Clearing her throat, she continued:
"My dearest sister,
Whether you can hear me or not, just know that I deeply apologize for all the pain I have caused you. First, it was the thousand years you spent on the moon, then the countless times I've started ridiculous arguments over ridiculous disagreements. But the worst pain you suffered at my hooves had to have happened the night you passed. I was too weak to fight, so you gave your life to protect me. Why? Why did you sacrifice yourself for somepony so fragile and weak? I didn't deserve to be saved. If anypony did, it was you. I would've died for you just as quickly as you died for me. Now, I'm all alone, in this state of pain, guilt, and sorrow, and it's all because I was too weak.
Just know that I'm truly sorry for all that has happened, and for causing your demise.
I love you, sister. Even if it takes a thousand years, I hope that someday, we'll meet again.
Your sister,
Celestia."
An uncontrollable stream of tears flowed from Twilight's eyes as well as Celestia's. However, she managed to recollect herself enough to lift the casket.
"Princess," she uttered, choking back more tears. "It's time."
Celestia said nothing. She simply nodded, and they escorted the late princess to her grave. Celestia was one of the few who hadn't yet seen the headstone, and the text brought her to another round of tears as soon as she finished reading it.
Princess Luna
Sister, friend, ruler of Equestria
"Until we meet again at the rainbow bridge"
The rainbow bridge was a myth told to the two sisters when they were just fillies. It was a bridge to the heavens, where every good pony would go after their burial.
Twilight saw the heartbroken expression on her mentor's face, and right after casting the last bit of dirt onto the grave, she walked right up to her and tightly enveloped her in her wings.
"I know how much it hurts," she whispered, her own voice beginning to quiver again.
"But, no matter how long it takes, there's always room to heal."
All Celestia could do at this point was bury her head into Twilight's shoulder, her emotions taking over her entirely this time.
Just then, it began to rain. Twilight looked up for a moment before whispering to Celestia again.
"See that? She misses you as well."
The End