Prologue
The beam of rainbow light subside, revealing a stone figurine in a laughing pose. There was a brilliant flash of light and the lands around the two alicorns returned to their original state after five long years.
Their work done, Celestia returned the six gems to her saddlebag, deciding to hold onto them rather than return them to their resting place, in the event they were needed again. The alicorn of the sun then shot a vicious glare and frown at the solidified form of her felled adversary. Finally, after all the mayhem and despair he had caused, they were rid of that treacherous draconequus. At last, his horrible reign had come to a merciful end and Equestria was free of his tyranny. Celestia continued to stare murderously at the wicked creature in its stone prison, her eyes cold, hard, and filled with hatred, her breathing heavy as it looked like she was snorting smoke through her nose. She glared at the stone creature so hard it was like she was trying to bore straight into it.
Then, after a full minute, her breathing calmed down, her glare slowly softened, and her frown grew as the tears she had been holding back all this time could no longer be suppressed and began to flow freely, her eyes becoming glossy. Closing her eyes, Celestia turned away from the frozen beast in front of her as her sniffling morphed into whimpering, her tears running down her cheeks and soaking her muzzle. Eventually, the tears began to drip to the ground as she started sobbing uncontrollably, throwing herself into her sister's hooves for comfort.
"I'm sorry, Sister" Luna said consolingly as she patted Celestia's back. "But it had to be done. There was no other way to resolve this. He had to be stopped. Just be thankful you don't have to do something that heartbreaking ever again."
"Why" Celestia moaned. "Why, Discord? Why?!" she angrily turned back to the frozen form of her greatest foe...and greatest love. "Why did you have to let yourself be corrupted by your hunger for power? Why couldn't you have choose to live beside myself and Luna and rule Equestria as equals? For five years, I've tried everything to make you come to your senses! Nothing worked and my subjects were the ones to pay the price for my indecisiveness! After you sicced your Cthulhu on myself and Luna and we barely escaped with our lives, I knew I had no choice but to get the Elements from the tree!" Celestia's anger changed into sadness as she continued talking "It didn't have to be this way, Discord! You could've remained my consort and we would be wed by now! Maybe even had a family! Now, despite you being right in front of me..."
"...we're worlds apart."
After finishing her rant, Celestia closed her eyes as she tearfully thought about the past she shared with the Spirit of Chaos before her: How she met him while exploring the Everfree Forest and how she found him the most unique and amazing creature she had ever seen, how she had convinced him to come back to the castle with her, how they grew up having the most amazing adventures alongside Luna, how she realized she was in love with him when he made the normally dull Grand Galloping Gala the most fun she'd ever had, and how she requested he become her consort and her joy when he accepted. Then, came the bad memories, how he started to become restless over not causing enough mischief, how he became jealous that she and Luna were rulers of Equestria, until finally, his chaotic magic reacted to his negative emotions and he became a crazy disharmonic overlord. Then the memories of the five years where she watched Discord torment her little ponies while she endlessly tried to convince him to return to his old self, only for him to laugh off her attempts, not remembering a thing about their past together. All those memories flowed through Celestia's mind, along with the pain of the fact that her dreams of their future together were gone forever, with only Discord's stone form being a symbol of what could have been.
Celestia had been focused on the memories of her past so much that she hadn't noticed that Luna had walked up beside her until she spoke. "What should we do with him now? Should we have him sent to Tartarus, or should we find a way to destroy the statue?"
"No" Celestia said as she shook her head, tears still falling from her eyes. "I want him where I can keep an eye on him. He will stay in the castle's garden, so I can keep a watchful eye on him and reminisce about the life we had together."
"Are you sure that's wise, Sister?" Luna asked cautiously.
"I know it would be wiser to dispose of him, but I just can't do it, Luna." Celesia admitted. "Somewhere, inside that cold, hard exterior is still the draconequus I love."
"But, dear Sister" Luna spoke "You've made endless attempts to bring back the good in his heart to no avail. I hate to tell you this, Sister, but I fear Discord is beyond saving."
"No." Celestia shook her head with determination "I'm not giving up on him." she stood up straight as she looked towards the sky. "One day, I will find a way to return him to the way he was. One day...we will be together again."
Luna could only stare at her sister, knowing that she had made her decision and that it was best to accept it.
Her only worry was if her sister was really being hopefully...
...or setting herself up for disappointment.