*Sonata Dusk is a female human and siren. She is a student from Canterlot High School and one of the main antagonists in the film My Little Pony Equestria Girls: Rainbow Rocks.

Throughout Rainbow Rocks, Sonata Dusk is shown to be somewhat air-headed and carefree, similar to Pinkie Pie. For example, before the Dazzlings sing Battle of the Bands in the cafeteria, Sonata is more focused on getting lunch since it is Taco Tuesday. Also, she and Pinkie are the only ones who actually seem to enjoy Snips and Snails' rap performance. Sonata doesn't pick up on Adagio's sarcasm when she says she "loves" the human world, and she speaks candidly with Sunset Shimmer about her and her friends' true nature, nearly blowing their cover. In addition, she frequently argues with Aria Blaze over trivial matters. Despite this, she can be just as cruel and devious as her bandmates, if at times unintentionally so, as evidenced in her interactions with Sunset and Trixie.

In Equestria, the sirens' true appearance is a Hippocampus. Upon releasing their full powers in the human world, the Dazzlings are shown to possess translucent fin-like wings in their anthro forms, unlike their true forms. Their siren forms are summoned as astral projections from their pendants and used to weaken the Rainbooms.

Arriving at Canterlot High, Sonata takes the appearance of a slender teenager with pale sky-blue skin, magenta-pink eyes with cyan upper-eyelids, and long, turquoise-blue hair with dark royal-blue streaks, kept into a high-ponytail with V-shaped bangs by a dark royal-blue hair tie. She dresses in a dark magenta vest with a brighter-colored popped-collar and cuffs, three pale sky-blue buttons with straps, and a light blue musical note surrounded by a brighter-magenta patch on the right side. She also wore a lavender-pink denim skirt, similarly-colored knee-high socks, and similar-length bright magenta high-tops with white soles and toes.

Sonata accessorizes with magenta bracelets with pale sky-blue spikes on both her wrists, and a black choker with a ruby pendant around her neck.*