Rita Repulsa is a female humanoid sorceress who was once bent on intergalactic domination and served as one of the leaders of the Evil Space Aliens and later joins the United Alliance of Evil. She's later purified into the Mystic Mother while her evil essence returns in the form of Robo Rita after possessing Alpha 8.

Rita has been a constant thorn on the sides of various Ranger Teams, most proeminently for the Mighty Morphin. But even when not making a physical appearance, her presence still echoed in other eras and caused trouble for other Ranger Teams such as Zeo, Turbo, In Space, Wild Force, Dino Thunder, Mystic Force, Operation Overdrive, Beast Morphers and Dino Fury. Altough on the case of Mystic Force, it was as a much needed ally.

And even when it's been thought that she's gone for good, she finds a way to come back. A prime example of this is when she, specifically her evil and wicked energy possessing an iteration of Alpha, came back in the form of Robo Ritta, 30 years after her defeat at the hands of the Mighty Morphin Power Rangers, more evil than before, even managing to kill the Yellow Ranger and almost doing the same to said Ranger's daughter.