Sunset Shimmer

"When the crown and its power are mine, Twilight Sparkle will be sorry she ever set hoof into this world... not that she would've been much safer if she'd stay in Equestria."

- Sunset

Sunset Shimmer is the (former) main antagonist in My Little Pony: Equestria Girls the tritagonist of its 2014 sequel, My Little Pony Equestria Girls: Rainbow Rocks and the main protagonist of the 2015 sequel My Little Pony Equestria Girls: Friendship Games, She also appeared in the IDW comics, where her backstory is detailed. She is a female unicorn pony and Princess Celestia's former student.

She is voiced by Rebecca Shoichet, who also provided Twilight Sparkle's singing voice.

Personality
Throughout the first film, Sunset Shimmer is shown to be mean, rude, short-tempered, arrogant, greedy, bratty, rebellious, boastful, cruel, sadistic, condescending, manipulative, and deceptive. She also doesn't believe in friendship, and is not willing to open herself up for any personal relationships. She frequently insults and belittles others, and thinks little to nothing afterwards. According to human Fluttershy, Sunset makes life miserable for "anyone who stands in her way". As a result, much of the Canterlot High student body is afraid of her. She is also shown to be mainly concerned with gaining power, desperately trying various attempts to get Twilight's crown in order to use its magic.

However, she doesn't appear to be willing enough to inflict physical pain on others, or at least not upon small animals (i.e. Spike), claiming she isn't a monster. She appears to be easily irritated when someone else is praised in her presence, to the point of being provoked into attacking them.

When Sunset puts on the element of magic, she transforms into a demonic visage of herself. While in this form, she becomes more dangerous and goes so far as attempting to kill Twilight and take her place. After she is defeated by the Elements of Harmony, Sunset Shimmer becomes immediately repentant and apologizes for her actions, appearing to renounce her prior dishonest and unkind ways. However, she is also overcome with a great deal of despair and regret. Almost everyone now turns their back on her, further complicating her sadness.

In the second film, Sunset Shimmer appears to have completely changed from her old self and started believing in friendship, becoming friends with her former enemies, even Twilight, and friendly, kind-hearted, humble, graceful, helpful, sensitive, caring, brave, and selfless. She also appears deeply repentant for her actions made at the end of the first film, referring to her altered self as a "raging she-demon". But since that time, she's felt troubled and her mind has become clouded with uncertainty. And no one has yet forgiven or forgotten her past actions. At this point, she runs into her new archenemies, Adagio Dazzle, Aria Blaze and Sonata Dusk. Sunset digs up the journal Celestia had given her and uses it to send out a distress signal. By the end of Rainbow Rocks, Sunset starts writing friendship reports to Princess Twilight using the journal she once used to communicate with Princess Celestia.

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

- Sunset Shimmer to Celestia

Sunset's backstory is explored deeper in the comics. Here, it is shown she had a very troubled relationship with her mentor Princess Celestia, which explains her descent into evil (though she was already extremely arrogant, self-centered, and antisocial, thus her mentor's short patience with her). Sunset had previously appeared in the form of a toy and as an NPC in the MLP Gameloft game. In both versions, she was merely a neutral character and not a truly evil one.

Sunset's desire was to gain princesshood and have everyone in Equestria recognize her. However, she felt Celestia's tutelage wasn't getting her anywhere fast enough. During the night, she took it upon herself to do research on the crystal mirror Celestia had shown her some time ago. Just as she found information about the mirror, Celestia and two royal guards arrived on the scene. At first, Celestia tried to console Sunset, but Sunset retaliated by demanding to be crowned a princess.

It was then Celestia saw that Sunset lacked all the qualities needed to be a true princess, and deemed the young unicorn unworthy of such a status. Celestia then expelled Sunset from the school, banished her from the castle, and had the guards escort Sunset out. Sunset told her former mentor that this would be the greatest mistake ever made, but of course it was only one of many. When the chance came, Sunset took the guards by surprise and jumped through the mirror -- emerging as a teenage girl on the other side.

My Little Pony Equestria Girls Movie
"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

Sunset Shimmer first appears as the main antagonist in the first film. She is a unicorn pony who steals Twilight Sparkle's element of harmony: her magic crown, and in a tussle with Twilight Sparkle, the crown is thrown into a mirror that acts as a portal to another world, which Sunset goes through to retrieve the crown. In this other world, she is depicted as a human who mocks Twilight Sparkle when they first encounter each other. They meet again in a dark hallway where Sunset bullies Twilight into being discouraged from retrieving her crown. Several years have passed since Sunset ran away from home. In the past, she drove the human counterparts of Rainbow Dash, Fluttershy, Applejack, Pinkie Pie, and Rarity apart, but Twilight reunites them. She tries to keep Twilight from becoming Princess of the Fall Formal, like humiliating her via internet video and implicating but Twilight Sparkle still easily beats her in the competition. When this attempt backfires, she makes her cronies, Snips & Snails vandalize the gymnasium and implicates Twilight for it via photo shopped photos. Vice-Principal Luna falls victim to this deception but Sunset's former beau, Flash Sentry, exonerates Twilight at the last second and Twilight is dubbed Fall Formal Princess after she and the student body clean and redecorate the gym.

However, Sunset steals the crown from Twilight Sparkle, puts it on, and transforms into a demonic-looking winged humanoid. In this form, Sunset becomes purely evil. With her new powers, she plans to use them and her army of mind-controlled teenagers to conquer Equestria. Sunset attempts to kill Twilight, but Twilight and her friends use the power of the Elements of Harmony to return her to human form. She is reduced to tears and apologizes for everything that she has done and Twilight believes her friends can help teach her the magic of friendship.

Afterwards, the human counterpart of Princess Luna, Vice Principal Luna, hands her a masonry trowel to repair all the damage that she caused. The worst part is, Sunset now feels like a nobody.

My Little Pony Equestria Girls: Rainbow Rocks
"I don't think anyone is supposed to have all the answers. But you can count on your friends to help you find them."

- Shimmer helping Twilight and her friends confront the Dazzlings.

Sunset Shimmer re-appears as one of the main protagonists in My Little Pony Equestria Girls: Rainbow Rocks, and was reformed from her villainous ways in the first film. With the exception of the Rainbooms, the rest of Canterlot High still bears resentment toward her and she even resents herself for the actions she'd taken as what she refers to as a "raging she-demon". She even admits to herself and her friends that she only dated Flash Sentry to make herself more popular.

When Sunset gives the Dazzlings (her archenemies) a tour of the school, she gets a bad vibe from them, even when Adagio Dazzle acted defensive about her pendant. Her suspicions are later confirmed when the Dazzlings mesmerize the students and faculty when they are singing. Using a magical book with her cutie mark on the cover, Sunset sends an SOS to Twilight Sparkle in Equestria. During Twilight's role as the Rainbooms' lead singer, Sunset acts in a supportive role and keeps an eye on the competition, especially the Dazzlings during the Battle of the Bands. At one point, Sunset Shimmer confronts the Dazzlings, who try to manipulate her insecurities by pointing out that the Rainbooms are reluctant to allow Sunset Shimmer into the band.

When the Rainbooms lash out at each other during the final round of the Battle of the Bands, Sunset realizes the Dazzlings' true intentions and is able to stop the arguing. She even accepts partial blame due to her lack of knowledge in friendship.

When the Dazzlings overpower the Rainbooms during the film's climax, Sunset Shimmer finally steps up and sings on the band's behalf. Her help not only gives the Rainbooms the strength needed to defeat the Dazzlings, but she also undergoes a half-pony transformation like her newfound friends. Afterward, Sunset Shimmer joins the band as a singer and guitarist, and she uses her old journal that she communicated with Princess Celestia through to write her friendship reports to Twilight Sparkle.

During the credits, Sunset is seen having now been accepted by the rest of the school, as the Cutie Mark Crusaders walk happily with her and Bulk Biceps helps her get Angel down from where he is stuck.

Sunset Shimmer is featured in the songs "Welcome to the Show" and "Shine Like Rainbows" during the film.

Powers and abilities
Throughout most of the film, Sunset Shimmer is in human form and devoid of magic, relying on manipulation and bullying to get her way. Her abilities as a unicorn are never demonstrated, but since she was Princess Celestia's personal student, it can be assumed they would be approximately on the same level as Twilight Sparkle's (before the latter became a Princess). Because of her Cutie Mark and her color scheme, it can be theorized she has an affinity to fire magic.

When Sunset Shimmer used the Element of Magic, she turns into a powerful, winged demonic entity with a fiery look. In this form, she can use immense magical powers, despite being in a magicless world. She is proficient with both Dark and Fire spells. She is able to effortlessly destroy walls with telekinesis, turn associates into a demon, brainwash large groups of people at once, and conjure powerful fireballs. Her only weakness in this form is that the Element is not "loyal" to her, since she does not grasp the magic of Friendship. When she tried to destroy Twilight Sparkle and her friends rush to her rescue, the magic of the Element refuses to harm them, instead imbuing the friends with power, despite Sunset Shimmer still wearing the crown.

It is demonstrated in Rainbow Rocks that she can use the power of the Elements of Harmony post-redemption, similarly to Twilight Sparkle.

In Friendship Games she uses Human!Twilight Sparkle's device in combination with her friends' magic to achieve a form known as Daydream Shimmer. In this form, she gains glowing wings of light, a long white horn and a regal gown. She can fire blasts of pure Harmony that counteract the dimension-destroying effect of Midnight Sparkle's chaos bolts, though Midnight Sparkle's sheer wrath and determination makes her more than a match for Daydream Shimmer.

Trivia

 * She is the first major female antagonist in the series who is not a monarch, the second being the Dazzlings and next Starlight Glimmer, Principal Abacus Cinch and Midnight Sparkle. Notable, none of Equestria Girls Villains are monarchs.
 * The way Sunset Shimmer is defeated is similar to Nightmare Moon. It is even possible that her demon form is the embodiment of her evil side, much like Nightmare Moon is considered the embodiment of Luna's jealousy, exorcised by the Elements of Harmony and purifying both (though it's also believed that the cause of Sunset's redemption was horror at what she became). It also was an homage to the first defeat of the villain in the series.
 * Before her redemption, she shared similarities with most of the main villains in the series so far: Nightmare Moon (past with Princess Celestia, seeking to rule over Equestria, and defeated in the same way by Twilight Sparkle), Discord (breaks friendships for the fun of it), Queen Chrysalis (manipulative, power-hungry, resorts to brainwashing), King Sombra (uses evil magic, seeks to conquer Equestria), and mostly Trixie (arrogant, insufferable, uses the power of a magical artifact that gives her immense power at the price of her sanity). She is also similar to Discord in that one of the Mane Six's actions was able to reform her; Fluttershy for Discord and Twilight for Sunset Shimmer.
 * Rebecca Shoichet, who does Sunset Shimmer's voice, also does the singing voice of Twilight Sparkle.
 * Sunset Shimmer can be considered an evil counterpart of Twilight Sparkle due to how many similarities they share. Some fans have speculated she is what Twilight may have become had she not discovered friendship and its meaning.
 * After starting to believe in friendship, Sunset Shimmer acts more like Twilight Sparkle, being the peacemaker of the group, having insecurities, and developing a worrisome personality. A difference is that Sunset is quite patient with the group's rage while Twilight is quite temperamental with hers.
 * Sunset Shimmer is the first main villain of a part of the series written by Meghan McCarthy who unambiguously survives. Lord Tirek and Adagio Dazzle follow.
 * Sunset Shimmer has many similarities from Golbez: (Became a very misguided and confused antagonist at debut, Once was a Clad in Dark: Her she-demon self, Felt horrified of her actions and feelings of hatred after snapping out of her misguided ways(cried about it after and because of her demon transformation), Becomes a caring, self-sacrificing, and empathetic friend, Unforgiven by everyone except Twilight's friends after the atrocities she made in her debut, Pays for her crimes by learning about friendship, relates to Twilight as she once was Princess Celestia's student, Twilight's friends forgave her after changing her ways, Found hope for the Rainbooms to defeat the Dazzlings, Everything she did was to save Canterlot High but became oblivious to the Dazzlings' evil schemes, Gave words of wisdom to her friends(but doesn't realize it), Made sure that her friends are safe, Had to live up for her crimes, Assisted the heroes and worked with them(Joined Twilight unlike Golbez in Dissidia), Swore to defeat the Dazzlings after the atrocities they made at Canterlot High, Summoned powerful magic to defeat the Dazzlings (god-like magical alicorn because of Sunset's singing), Saved the day in the end, feels sorry for the Dazzlings, has to work on friendship, Had to do something about her past(erase it). The only difference is that she sums up Garland in Final Fantasy perfectly during her debut in terms of actions and personality
 * Demon Shimmer, "she-devil" alter-ego of Sunset Shimmer in her demon form is one recurring symbol of "Equestria Girls" - being the real villain in the first movie like Nightmare Moon, she was then the reason of Sunset Shimmer being an outcast among the students in "Rainbow Rocks", also, she is mentioned and seen in clip "My Past is Not Today" at evil of Sunset. In "Friendship Games" her picture, along with the Dazzlings, appears in Rainbow Dash's song to cheer other up. Also, Midnight Sparkle is obviously has the same nature as Demon Shimmer, being the user of twisted power of the Friendship Magic.