Adagio Dazzle is the leader of the band "The Dazzlings" in Equestria Girls: Rainbow Rocks. She, along with Aria Blaze and Sonata Dusk,were sirens which had the power to charm ponies with their music: But, to gain this, they fed on the negativitey and distrust of others.

They were soon banished by Starswhirl The Bearded to another world, where Caterlot High is situated. Here, taking the form of humans, they fed on the negativity via a red jewel around their neck.

Out of the 3, Adagio is the more manipulative and "bossy" of the band. She is constantly fed up with both Sonata and Aria's antics.

Adagio (in music terms) means "slow".