Bluebird

Bluebird Azurite, or just Bluebird for short, is one of the main antagonists of the 2019 limited series, Steven Universe Future, appears as the titular main antagonist of the episode Bluebird. She is a fusion of the two vengeful gems Aquamarine and Eyeball Ruby, who first seems to be very kind and sweet, however Bluebird was revealed as a very cruel gem.

She is voiced by Larissa Gallagher

History
She came to Steven in the epsisode Bluebird, and attempted to trick Steven into thinking she has changed to a good gem, until they attempt to kill Greg and turn Steven evil. They fight Steven and the Crystal Gems find out, fusing into Alexandrite and defeating the two. They both then fly off into the distance to escape.