This story is also on fimfiction under the name "A Better World". My account on there is The Spirit of Evil.

"I can say without a doubt that there are an infinite number of universes

Some are just like our own.. but for one or two significant events, exactly the same."

-Lex Luthor

"This day has been just perfect! The kind of day of which I've dreamed since I was small. Everypony I'll soon control! Every stallion, mare, and foal! Who says a girl can't really have it all?" Chrysalis sang gleefully.

Snorting in disgust, Twilight turned her attention to Cadence, stuck in green changeling goop. Shining Armor stood beside his would be bride, his eyes in Chrysalis' trance. Twilight quietly snuck past Chrysalis over to Cadence.

"Quick, go to him while you still have the chance!" Twilight whispered, freeing Cadence from the goop. Cadence nodded and trotted over to Shining, gently caressing his face. He gave no response, his eyes indicating he was still hypnotized. Tears formed in Cadence's eyes as she hugged him. Her horn sparked, and love magic flowed from her to him.

Shining blinked his eyes open, as if seeing everything for the first time. "Where? Huh? Is- is the wedding over?"

"It's ALL over!" Chrysalis landed in front of them with an angry expression.

"Quick! Perform your spell!" Twilight said urgently. Behind her her five friends nodded in agreement.

Shining's horn sparked as he tried to channel his magic. "I-I can't! My power is useless now... I don't have the strength to repel them!"

Candence held him close. "My love will give you strength!" She connected her horn with his, and the spell began glowing between them.

CRACK! A green flash blasted them apart, throwing Cadence and Shining against the wall. "I don't think so!" Chrysalis yelled.

"No!" Twilight screamed as her brother and would be sister-in-law lay dazed on the floor.

The changeling queen laughed. "Did you really think I'd be foolish enough to let them perform their love spell? Now let me show you what REAL strength is!" Chrysalis looked up at the ceiling, where Princess Celestia hung from a small cocoon. The cocoon was enveloped in a green aura and levitated toward Chrysalis.

"What are you...?" Fluttershy asked fearfully.

"Say GOODBYE to your precious princess!" Chrysalis smiled malevolently. She opened her mouth and a pink mist began to flow from Celestia's heart.

"Stop!" Rainbow yelled, flying at Chrysalis. The queen simply waved her hoof and Rainbow was magically thrown aside.

The pink mist continued to to drift into Chrysalis' greedy mouth as Celestia began to turn a shade of black. Twilight angrily shot a stunning spell, but it was deflected away. "Foolish ponies. You know it's funny really, do you know how many times Celestia defeated me before this? I counted. Two hundred times." The ponies looked at each other nervously. "Oh don't looked so surprised, she and I have been doing this for thousands of years. Every time, Celestia and her little pony allies would repel me with their love, and no matter how many cities I took, they eventually drove me away. That's why I attacked her precious capitol from the inside by using this pitiful wedding as a distraction."

"We-we'll stop you again!" Applejack said defiantly.

"You little ponies are so predictable. Every one of Celestia's little goody goodies said the same thing. No matter how many times they stopped me, it was only a matter of time before I outlived them. No matter how many prisons Celestia put me and my brood in, we would escape and try again, and again until finally we managed to get the upper hoof! Why? Because she didn't have the guts to do THIS!"

The mist stopped flowing, and Chrysalis hurled the now blackened Celestia at Twilight's hooves. Twilight desperately felt Celestia's chest for heartbeat, but all she heard was silence.

"You-you killed her!" Twilight yelled tearfully. Her friends gasped, looking appalled.

Chrysalis tilted her head looking confused. "I did? How unexpected... I drained her love not her life." She shrugged nonchalantly. "I suppose when you take away the love there isn't much left in you little ponies, is there?" Chuckling to herself, Chrysalis looked out the window, watching her changelings ravage Canterlot.

"You're a monster!" Rarity screamed, tears streaming down her cheeks as she looked at the fallen princess.

"A monster? Please. My changelings were denied sustenance, so I took it by force! Now you ponies will pay the price for exiling us!" Chrysalis hissed.

Emotions churned in Twilight's heart, as she looked at her fallen mentor. Memories from her childhood in the castle flashed through her mind. She heard Celestia's gentle laugh, remembering all their fun games and study sessions together. Celestia's kind, wise and caring face had always been there to look up to. Even in her darkest moments, Twilight knew that her mentor was as ever-present as the sun, always watching over and guiding her. Now that mentor was gone. She would never hear Princess Celestia's laugh, her words of wisdom, never feel her embrace again. Sadness and loss twisted inside her, twisted into something else. Something red, hot and powerful like the Sun. Rage.

Twilight stepped up to face Chrysalis with a steely look in her eyes. Magic began channeling at her horn, a large purple mass crackling with energy.

"You little foal!" Chrysalis laughed. "I've absorbed the power of Celestia herself! What makes you think you could stop ME?!"

Twilight spoke in an even, almost emotionless tone. "You're right Chrysalis. Princess Celestia could never have stopped you, because she couldn't do what needed to be done... but I CAN!" The magic on Twilight's horn turned a dark, smoky black color and blasted toward Chrysalis.

Before she could react, the magic hit Chrysalis square in the chest, and she instantly burst into black flames. She began screaming as everypony looked on in horror and fascination. "H-HOW?!" she screamed.

"You may have Princess Celestia's power Chrysalis, but I carry within me the most powerful magic of all. It was just a matter of realizing its TRUE power."

"Ahhhh!" Chrysalis stumbled around, the flames intensifying more and more. "Please! Stop, I'll do anything!" she begged.

"I realize now, why after thousands of years Princess Celestia wasn't able to bring Harmony. She wouldn't put an end to creatures like you. But I will." The black fire burned brighter around Chrysalis, and with an agonized scream she was turned into a smoldering pile of ash.

"T-Twi? Did you just...?" Fluttershy asked timidly.

"Well, it had to be done." Applejack stated flatly, taking off her hat in deference to the fallen princess.

"I'm sorry Twily." Shining trotted over to Twilight and hugged her sadly. Sometime during the battle he and Cadence must've regained consciousness.

"She- she didn't die for nothing Twi... she spent her life protecting Equestria, bringing Harmony." Cadence said mournfully.

Twilight looked up with a grim expression. "No, she didn't die in vain. We'll make sure of that. Equestria will have Harmony... one way or another."