Sunset Shimmer

Sunset Shimmer is a female unicorn and the main antagonist in My Little Pony Equestria Girls.

Development
Sunset Shimmer resembles the G3 Earth pony Sunshimmer in pony design and name.

An image of human Sunset Shimmer that appears on the back of the Equestria Girls Sunset Shimmer & Twilight Sparkle doll release's packaging was posted online in mid-March 2013.

On March 19, 2013, Meghan McCarthy was asked "Is Sunset Shimmer going to be a Season 4 storyline? The fact that her backstory seems like a show plot" and responded "Nope." On April 1, 2013, McCarthy wrote as part of an April Fools' Day joke that My Little Pony Friendship is Magic season four episode five would be titled "The Student Becomes the Teacher: The Return of Sunset Shimmer".

Depiction in the film
Sunset Shimmer appears in the film My Little Pony Equestria Girls as the main antagonist. She is a pony who steals Twilight Sparkle's element of magic crown, and in a tussle with Twilight, the crown is thrown into a mirror that acts as a portal to another world, which Sunset goes through to get the crown.

Celestia reveals that Sunset was a former student of hers, who began her studies not long before Twilight did. However, when she did not get the things she desired as quickly as she'd liked, she turned cruel and dishonest, eventually deciding to abandon her studies and pursue her own path.

In this other world, Sunset has been living as a human for some time, and has won Canterlot High's Princess of the Fall Formal three times in a row. She discovers that Fluttershy had found the crown and turned it over to Principal Celestia, much to Sunset's annoyance, as she wants to use the crown for its magical properties as to create an army of teenagers to invade Equestria through the portal. Principal Celestia believes the crown is the same as the prop used as the award for the Fall Formal, but is unaware of its true origins.

Learning that Twilight will be competing against her for the title of Princess of the Fall Formal, Sunset tries many ways to hinder and humiliate Twilight, such as releasing videos of Twilight struggling to get used to the human world taken by Snips and Snails, and doctoring photos to frame Twilight for ruining the dance decorations. But her friends help to counter these ploys by improving Twilight's reputation and Flash Sentry, Sunset's ex-boyfriend, proves that Twilight is innocent.

At the Formal, Twilight is named the Princess and given the crown, but Sunset has Snips and Snails kidnap Spike and threatens to destroy the portal to Equestria unless Twilight gives her the crown. When Twilight refuses to give her the crown, stating that her being stuck would be worth stopping Sunset, and her friends congratulate her bravery, Sunset snaps and attacks her. The others aid Twilight in keeping the crown away, but Sunset manages to don the crown. However it did not go as she expected, as she began to shed tears as her darker side takes over and transforms her into a demonic shape. She transforms Snips and Snails into minions with similar appearances, and quickly uses her newfound powers to destroy part of the school and brainwash the other students at the school. She then reveals that she never intended to destroy the portal, and will use her teenage army to conquer Equestria.

Twilight is able to evoke the Elements' magical powers when her human friends move to defend her from Sunset Shimmer's attack, temporarily transforming the six into pony-like humans and wielding a power through their friendship that is able to exorcise the demonic form from Sunset, Snips, and Snails, and revert the rest of the students to normal.

As everyone recovers, a repentant and traumatized Sunset is reduced to tears and asks for forgiveness to which Twilight replies by asking her friends to become Sunset's new friends, something she hasn't had before. Sunset, Snips, and Snails are then tasked by Vice-Principal Luna with rebuilding the school that they have destroyed.

Depiction in the comics
An eight-page featurette included with, titled "The Fall of Sunset Shimmer", details Sunset Shimmer's last days as Princess Celestia's student.

Like Twilight, Sunset is shown to be a magical prodigy. Unlike Twilight, however, she's quite boastful and condescending toward others, despite Celestia's lessons about humility. Celestia shows Sunset the magic mirror from the film; in it, Sunset sees herself as an all-powerful alicorn—one who could rule Equestria. Sunset briefly sees something else in the mirror, but Celestia guides her away from it before she gets too curious. During the weeks that follow, the mirror is all Sunset can think about, and Celestia repeatedly tells her that she'll learn about the mirror and other lessons "when [she's] ready".

An undeterred Sunset Shimmer begins researching the mirror behind Celestia's back, but is soon caught by the princess and her royal guards. Sunset berates her teacher for hiding such magic from her and demands to be made a princess. Celestia refuses, saying that being a princess must be earned, and removes Sunset from her position as her student. She has the royal guards escort Sunset out of the castle, but Sunset overpowers the guards and escapes through the mirror.

As Celestia has the mirror moved to her throne room, Sunset Shimmer emerges in the human world as a teenage girl.

Personality
Much like Trixie before her redemption, Sunset Shimmer is the opposite of Twilight; cruel, arrogant, selfish, bullying, and jealous. While she is willing to harm and humiliate anyone in her way, she still had a limit, as she was not willing to use hostages. However when she tried to use the element of Magic, it drew out a demonic visage of herself, and she became far more violent and cruel, trying to kill what seemed to be a defenseless opponent. This seemed against her will, as this transformation pained her so terribly it drew her to tears. After she is purified she becomes repentant, likely because she was horrified and disgusted that her darker tendencies turned her into a true monster, and pleads for forgiveness. Like Twilight in the beginning of the series, she didn't know the first thing about friendship and like Discord, she never had a real friend before.

My Little Pony (mobile game)
Sunset Shimmer is one of the available playable characters in Gameloft's mobile game. She was added to the game on June 13, 2013. According to her in-game description, "Sunset Shimmer is one of the most promising students at Princess Celestia's school for gifted unicorns. Her cutie mark is a shimmering sun." In the first week of June 2013, Hasbro's My Little Pony Facebook page and the official Facebook page of the game posted the clues "The path to a new adventure is magical...", "Everyone will love me now!", "Beware, Equestria!", "A beautiful pony that has nothing but power and potential", "I'm better than all of you!", and "Magical mirrors shimmer".

Merchandise
A Playful Ponies toy of Sunset Shimmer was displayed wearing a masquerade mask at the 2013 New York Toy Fair, and was released with the mask and a comb as part of the Crystal Princess Celebration line. The back of the release's packaging bears the general statement "The ponies wear beautiful masks to dress up for a special celebration!" and the specific statement "Sunset Shimmer knows a magical path to faraway adventures! Years ago, she was also a student of Princess Celestia."

An Equestria Girls human doll of Sunset Shimmer is to be released with another such doll of Twilight Sparkle and other items, including an element of magic crown accessory. Sunset Shimmer's description on the back of the release's packaging reads, "Her striking sense of fashion steals a lot of attention!"

Quotes
"Sorry it had to be this way... Princess!"

- To Twilight Sparkle, My Little Pony Equestria Girls

"You really are pathetic. It's no wonder your best friends are all stray animals."

- To Fluttershy, My Little Pony Equestria Girls

"You must be new here. I can speak to anyone any way I want."

- My Little Pony Equestria Girls

"This looks terrible! There should be more streamers near the stage and fewer balloons."

- To Pinkie Pie, My Little Pony Equestria Girls

"You country folk really aren't that bright. Must be why the other students say such awful things about you."

- To Applejack, My Little Pony Equestria Girls

"Twilight Sparkle wants to be your Fall Formal Princess. What does it say about our school if we give someone like this... such an important honor?"

- Voiceover in an anti-Twilight Sparkle video, My Little Pony Equestria Girls

"Take those off! I have something I need you to do."

- To Snips and Snails, My Little Pony Equestria Girls

"Spoiler alert: I was bluffing when I said I was going to destroy the portal. I don't want to rule this pathetic little high school; I want Equestria! And with my own little teenage army behind me, I am going to get it!"

- My Little Pony Equestria Girls

"I'm sorry. I'm so sorry. I didn't know there was another way."

- After being defeated by Twilight and her friends, My Little Pony Equestria Girls

"But... but all I've ever done since being here is drive everyone apart. I don't know the first thing about friendship."

- My Little Pony Equestria Girls

"Hmpf. I have better things to do than socialize. I'm going to re-read 'Advanced Elemental Magical Practices' and then practice for my advanced summoning spells exam. What are you studying for? Nothing, that's what."

- The Fall of Sunset Shimmer

"I deserve to stand beside you and be your equal... if not your better. Make me a princess."

- To Princess Celestia, The Fall of Sunset Shimmer

"Well, well, this is an interesting development."

- Upon arriving in the human world, The Fall of Sunset Shimmer

"Twilight Sparkle thinks she can win Fall Formal Princess over me? HA! I'm going to rule this school once I get that crown!"

- Thought, Sunset Shimmer & Twilight Sparkle doll packaging