Adagio Dazzle is shown to be scheming, manipulative, and only concerned with being adored by others. Using her dark magic and seductive nature, she is able to sway people's opinion with ease. She also has a considerable level of intelligence, as she quickly recognizes Steven Universe as a source of magic, and often the one working out the plans for the Dazzlings.
Adagio bears contempt toward her fellow sirens Aria and Sonata, calling them "idiots" and generally disliking their company. As the leader she is shown to grow irritated when her authority is questioned, especially from Aria Blaze.
Prior to the series, she and her sisters used to live out in the oceans of Equus, but was driven into Equestria's dry land due to Leviathan's invasion and takeover of the sea. Still, she and her siblings attempt to take over Equestria with their dark magic, only for the Pillars of Equestria to transported them into Earth, turning her and her sisters into Humans.
Despite this, the Dazzlings had become quite popular in their world.
Adagio Dazzle is the first of the Dazzlings to appear, shown by herself in one of Sour Cream's RAVE's, and attempting to seduce Jamie during her time there, using her magic to effect his fondness for her and starting a riot while there due to the same magic.
She reappears within Beach City's Funland along with her sisters, performing there and starting a riot all the while to create even more energy, despite not being able to feed off of it due to the Everstorm's presence. She creates the goal of taking over Beach City, but despite causing much havoc, was ultimately driven away when Blue destroyed the Dazzlings' amulets.
After their defeat in Beach City, she and her sisters were found in Fairfax and despite their involvement in Beach City, was taken in by Vidalia as they didn't have a home. While she was resistive for having Steven Universe being their new roommate, even saying she didn't need a "third wheel", she quickly realized that Steven was potentially their ticket to get back to Equestria, working the plan to her sisters to play it nice with him so he can take them back. This included going with him to the Fairfax Ski Resort on request, and staying behind with her sisters to look for him when he went missing.