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 posted online in mid-March 2013 depicts human Sunset Shimmer with pony ears and longer hair, similarly to the six main characters of Equestria Girls in part of the film and in some other material.

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 power 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 the 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 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 humiliate Twilight, such as releasing videos of Twilight struggling to get used to the human world and framing 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. When Twilight refuses to give her the crown, stating that her being stuck would be worth stopping Sunset, Sunset snaps and attacks her. The others aid Twilight in keeping the crown away, but Sunset manages to don the crown, and transforms into a demonic creature. 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. Twilight and her five new friends are able to recover the crown, but Sunset remains as a demon. Twilight is able to evoke the Elements' magical powers, 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 and revert the rest of the students to normal.

As everyone recovers, a repentant Sunset is reduced to tears asks for forgiveness, and Twilight asks 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.

Personality
Much like Trixie before her redemption, Sunset Shimmer is the opposite of Twilight; cruel, arrogant, sadistic, malevolent, selfish, jealous, bullyish, and mean-spirited. Her cruelty, sadism, selfishness, and bullyish behavior is shown when she ridicules Fluttershy as a human while interrogating her and when she tries to embarrass Twilight. Her malevolent side takes over when she gains possession of the element of magic. At the film's end, after her defeat, she becomes remorseful and comes to the realization that friendship is the most powerful magic and, like Discord, has never had a friend in her life.

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."

A doll of human Sunset Shimmer is to be released with a doll of human Twilight Sparkle and other items, including an element of magic crown accessory from Equestria Girls.

Quotes
"You must be new here."

- Both trailers

"Where is this Twilight Sparkle?"

- First trailer

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

- Sunset Shimmer to Snips & Snails

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

- Sunset Shimmer crying after being defeated by Twilight and her friends

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

- Sunset Shimmer explaining she didn't understand about friendship