The pony Twilight Sparkle is the main protagonist of the Equestria Girls series. Other ponies from the original My Little Pony show who make an appearance in the "Rainbow Rocks" film are Rainbow Dash, Pinkie Pie, Fluttershy, Applejack and Rarity.
"Rainbow Rocks," a spinoff of the My Little Pony series which features human versions of the pony characters, has many of the ponies from the MLP franchise. Each of these ponies are in human form for this film. Together, they are all in a band called the Rainbooms. There is an unnamed pony who plays DJ in this band, but fans often call her Vinyl Scratch or DJ Pon-3.
Versions of Princess Celestia and Princess Luna also appear in this film as the human principal and vice-principal of the school. Sunset Shimmer, the pony responsible for causing the transformation into humans in the original Equestria Girls film, also appears in this sequel. Spike, Twilight Sparkle's dragon friend, becomes a dog in this universe and appears in both films.
A rival band features several major characters who were not ponies in the original franchise. The Dazzlers are headed by Adagio Dazzle and her friends Sonata Dusk, Aria Blaze, and Flash Sentry. The Dazzlers are evil magicians who are assisted by Trixie Lulamoon, who appeared in pony form in the original series.
Other minor characters from My Little Pony, such as Apple Bloom, Maud Pie and Photo Finish, also appear as human versions of their pony character.