Despite her name, Sour Sweet is very arrogant, rude and sarcastic.
She is very competitive and loyal when it comes to winning, and she will use any means to do so, during the games she criticizes and insults Twilight a lot for her clumsiness of her believing that because of her they will lose, this means that she is also she cynical.
She also proves manipulative in using Twilight to win the Friendship Games to win Crystal Preps.
However, she is respectful and protective of her peers, and proves that she is not entirely hateful when Twilight with the stolen magic she cannot control transforms into the evil Midnight Sparkle who intends to destroy the two dimensions, where she rushes to rescue. his comrades and even his rivals who are about to fall to death in the other world, hanging on to what he has done.
In Dance Magic she shows that she hasn't completely changed since the events of Friendship Game, she is still a little bit sharp and competitive, as shown that she already steals the idea from Raity to participate in the dance competition. But she regrets doing it because she just wanted to help her teammates, and she and the others make the video together with the Human 7 to win.
Sour appears as the leader of Crystal Preps' Shadowbolts to go win the Friendship Games, complains to Twilight when she accidentally cuts her way to the bus to Canterlot High School, and is rude to let her go. forward.
In the Decathlon Academic woodcut game he pairs up with Sunny Flare, but fails in the spelling bee part.
Principal Cinch pairs her up with Twilight in the Tri-Cross Relay, where Sour quickly hits the target and gets mad at Twilight when she can't keep up and for taking advice from Applejack having hit the mark. She also becomes annoyed by Twilight's talking dog, Spike, complimenting her.
Eventually, when it comes to the end of the games and they all gather into their teams, they tell Twilight to release the stolen magic, but the situation gets out of hand and she turns into the frightening Midnight Sparkle, of which Sour Sweet is horrified by it. Sour and her teammates rush to save their teammates and the Canterlot High boys who risk dying with the help of Pinkie Pie.
After Twilight is back to normal, Sour and the girls at Crystal Preps regret being so rude by admitting their mistakes, only to later blame Cinch for the disaster that happened. She was last seen with Upper Crust and Dean Cadence talking before returning to Crystal Preps.
Sour Sweet is together with Lemon Zest, Sunny Flare and Sugarcoat they meet Rarity at the Canterlot shopping center who signs up for the dance competition, and among the various chats they are already thinking of stealing her idea for video. Then in the end, it turns out that they only did it for their friends and they join the Rainbooms to make that video.