Here is Adagio Dazzle the siren, leader of the Dazzlings captured in a burqa.

Adagio Dazzle is a female siren and the main antagonist of My Little Pony Equestria Girls: Rainbow Rocks. She is the lead singer of her band the Dazzlings, rivaling the Rainbooms.

Throughout the film, Adagio Dazzle is shown to be scheming, manipulative, and only concerned with being adored by others. Through her dark magic, she is able to sway the students’ opinion with ease and trick Trixie into removing the Rainbooms from the competition. She also displays a degree of sadism, seen when taking advantage of Sunset Shimmer’s insecurities, and a considerable level of intelligence, as she quickly recognizes the Rainbooms as a source of magic. Adagio bears contempt toward her fellow sirens Aria and Sonata, calling them “idiots” and generally disliking their company.

The Dazzlings, including Adagio Dazzle, Sonata Dusk, and Aria Blaze, appear in My Little Pony Equestria Girls: Rainbow Rocks as the main antagonists; Adagio Dazzle is shown on the cover of its novelization My Little Pony: Equestria Girls: Rainbow Rocks: The Mane Event.
In the film, Adagio and the other Dazzlings are introduced in the human world. They are sirens from Equestria who were banished to the human world by Star Swirl the Bearded. They are first seen in a café causing tension between the patrons when they witness the Equestrian magic that brought Sunset Shimmer to her downfall inthe first film. Some time later, the reformed Sunset gives a tour of the school to Adagio and the other Dazzlings and tries to be friendly, but she gets suspicious when Sonata randomly blurts out that they sing to “get people to do what [they] want” and Adagio gets defensive over her pendant. Soon after, they convince all of the students except the Rainbooms and Sunset with their music to turn the friendly Musical Showcase into an all-out Battle of the Bands.
Adagio and the Dazzlings use their siren’s songs to control student opinion and advance through the competition bracket. When the only bands between them and first place are the Rainboomsand Trixie and the Illusions, Adagio manipulates Trixie into removing the Rainbooms from the competition entirely. In the final battle against the Rainbooms, Adagio and the Dazzlings are eventually defeated, and the gem pendants with which they controlled the students are destroyed. As a result, their inability to sing leads to them being chased off in disgrace.
Aside from flashbacks, Adagio’s true form is never physically shown in the film, but she and her fellow band members gain pony-like ears, extended ponytails, and translucent fin-like wings. They also summon astral projections of their true siren forms from their pendants.