Sunset Shimmer appears as the both primary and main antagonist in Twilight and Kyle's Beginning of Equestria Girls. She is Anubis and Venom's friend, and Set's Heylin apprentice which her order of her master is steal Twilight Sparkle's element of magic crown and during a tussle with Twilight, the crown is thrown into the Crystal Mirror that acts as a portal to the human world. She then follows the crown shortly after.
Her former teacher, Princess Celestia, reveals that Sunset was a former student of hers who began her studies not long before Twilight did. However, when she didn't get what she desired as quickly as she wanted, she turned cruel and dishonest, eventually abandoning her studies to pursue her own path. In this other world, Sunset has been living as a human where she joined Set's army of Heylin Empire as his young Heylin apprentice, and a student of Canterlot High School for some time. She discovers that Fluttershy found the crown and turned it over to Principal Celestia, much to Sunset's annoyance.
After learning that Twilight and Kyle Akers (son of Pitch Black and Eris) will be competing against her for the title of Princess of the Fall Formal, Sunset employs various ways with help of her fellow Heylin villains such as Chase Young, Shadow, Lord Hater, Commander Peepers, Boogey, King Ghidorah and Doctor Octopus to hinder and humiliate Twilight and get rid of Kyle. She has Snips and Snails record embarrassing videos of Twilight struggling to get used to the human world and releases the videos online, and she doctors photos to frame Twilight for ruining the dance decorations. But Twilight's friends and allies help to counter these ploys by improving Twilight's reputations, and Flash Sentry, Sunset Shimmer's ex-boyfriend, helps prove Twilight's intocence.
At the Fall Formal, when Twilight is named princess and given the crown, Sunset has Snips and Snails kidnap Spike and threatens to destroy the portal to Equestria unless Twilight gives her the crown. Twilight refuses to give the crown up, stating that her being stuck in the human world would be worth stopping Sunset. As Twilight's friends and allies commend her bravery and sacrifice, Sunset snaps and attacks her. Despite Twilight and her friends and allies' efforts while fighting against Chase Young, Shadow, Lord Hater, Peepers, Boogey, King Ghidorah and Doc Ock, Sunset succeeds in getting the crown and puts on it. Unfortunately the magic from the crown is unstable for anyone, besides Twilight, to wear it. So a dark Heylin magic aura from it transforms her into a demon, betraying and killing Chase along with it. With her newfound powers, Sunset transforms Snips and Snails into similar-looking minions and brainwashes the other students at the school. She reveals that she never intended to destroy the portal and plans to invade and conquer Equestria with her army of teenagers for her lord and master, Set the Egyptian God of Chaos and master of all Heylin side.
Twilight is able to evoke the powers of the Elements of Harmony when her friends move to protect her from Sunset Shimmer's attack. Temporarily given pony-like characteristics, they use the magic of friendship to defeat Sunset Shimmer and returns Snips, Snails, and the rest of the students to normal.
As everyone recovers, a beaten and repentant Sunset is reduced to tears and apologizes to everyone she's hurt. She admits to not knowing anything about friendship, to which Twilight says her friends and allies can teach her. Sunset, Snips and Snails are later tasked by Vice Principal Luna with rebuilding the part of school they had destroyed during their attack as detention/punishment.
Sunset Shimmer re-appears in Twilight and Kyle's Adventures of Equestria Girls: Rainbow Rocks, reformed from her villainous Heylin ways in the first film. With the exception of the Rainbooms and Team Owl, the rest of Canterlot High bears resentment towards 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 and allies that she never had a romantic interest in Flash Sentry and only dated him to make herself more popular. Therefore, Wander started to have feelings for her, even crush on her.
When Sunset gives the Dazzlings a tour of the school, she gets a bad vide from them when Adagio Dazzle gets defensive about her pendant. Her suspicions are later confirmed when the Dazzlings mesmerize the students and faculty with their singing. Using a magical book with her cutie mark on the cover, Sunset sends an SOS to Princess Celestia in Equestria. During Twilight's role as the Rainbooms's lead singer "and" team leader, Sunset acts in a supportive role and keeps an eye of the cometition, especially the Dazzlings and the villainous Heylin Warriors during the Battle of the Bands. At one point, Sunset confronts the Dazzlings, who try to manipulate her insecurities by pointing out that the Rainbooms and Team Owl were reluctant to allow Sunset into the band/team.
When the Rainbooms and Team Owl lash out at each other during the final round of the Battle of the Bands, Sunset realizes what the Dazzlings' true intentions are and is able to stop the petty arguing. She even accepts partial blame due to her lack of knowledge of friendship.
When the Dazzlings and their army of Heylin Empire resurrects Chase Young from the dead and overpower the Rainbooms and Team Owl during the film's climax, Sunset Shimmer steps up and sings on the band/team's behalf. Her help not only gives the Rainbooms and Team Owl the strength they need to defeat the Dazzlings and the evil warriors of Heylin Empire, but she also undergoes a half-pony transformation like her friends. Afterward, Sunset joins the band/team as a singer and guitarist, and she uses her old journal that she communicated with Princess Celestia through to write her friendship reports to Princess Twilight Sparkle.
During Shine Like Rainbows, the rest of the school now accepts Sunset. The Cutie Mark Crusaders walk happily with her after Apple Bloom catcher her journal when it falls out of her backpack, and Bulk Biceps helps her get Angel down from a hard-to-reach perch.
In the Adventure Series, as Twilight returned to the human world to see her human friends and allies, Sunset Shimmer became Twilight's second-in-command of the Rainbooms, as well as her "sister". Wander then grows more feelings towards her, as he and Sunset started their relationship.
- Sleeping Lion
- Yellow lightsaber
- Geode; The Magic of Mind Reading
- Mind Reader Conch (Sunset's main Shen Gong Wu)
- Electric Guitar
- Assault Rifle
- M6 Magnum
- Battle Rifle
- Plasma Rifle
- Energy Sword
List of cards:
- Her friends and family
- Studying and learning about friendship
- Anubis the God of Death
- Set the God of Chaos
- Equestria Girls villains
- Chase Young
- Master Xehanort
- Drago Bludvist
- Being treated like a bad person again
- Sunset Shimmer will become Jeffrey and Jaden's enemy in Xion's Ohana Adventures of Equestria Girls.
- Sunset Shimmer will return in Xion's Ohana Adventures of Equestria Girls: Rainbow Rocks. Xion will try to reform her like how Fluttershy and Beetles reformed Discord.
- After Sunset Shimmer reformed, like Ralphie and Discord, she and Twilight are very good best sisters and friends to each other since they're both leaders of the Rainbooms and a great female duo.
- In Twilight and Kyle's Adventures of Equestria Girls: Friendship Games, Sunset will defeat Midnight Sparkle and Ultron in her powerful form named Daydream Shimmer.
- In the Thunderbolts Adventure Series, Courtney accepts her as a part of the family after what she did in the past. She'll also be an aunt to Sofia, Ryan, and Baby Skye.