Throughout the film, Sonata Dusk is shown to be somewhat air-headed and carefree, similar to Pinkie Pie. For example, before the Dazzlings sing Battle 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 Shimmer and Trixie.
Like those of her bandmates Adagio Dazzle and Aria Blaze, Sonata Dusk's fin-like wings are translucent and non-feathered.
In music terms, the word "sonata" refers to a composition for an instrumental soloist, often with a piano accompaniment.
Both the original animatic of the opening credits and the doll merchandise depict Sonata wearing purple tinted sunglasses. On the doll, her blue belt also is slightly different as her belt hangs off her waist with cutie mark chains hanging off of it. Only her blue belt appears in the final film.