Rita Repulsa was an evil witch who plagued the galaxy thousand of years before. She lost a battle to her rival, Zordon. Zordon had her trapped in an interglatic dumpster. She was able to trap Zordon in another demension before he exiled her. Rita was freed years later and immedtaly attacked earth. Zordon's Power Ranegrs were able to stop her at every turn. Later she sent her own evil green ranger to destroy the rangers.The ranegrs were able to break the evil spell Rita had on her evil ranger. This allowed the green rangers to jion the other Power Rangers. Rita later drained the green rangers enrgy. He was later able to return due to a charge from Zordon and the power cions (although his power suply was limited).
Rita was eventully locked away again by her boss Lord Zedd. Zedd took over he duties of conquerng the Earth. Rita would later return and give Zedd a love potion making him in love with her. The two would marry and continue to challenge the ranegrs together. A few yeas later the Machine Empire ran them out of the solar system. They returned and got their revenge. During a big battle betwen good and evil Zordon's energy wave turned Rita and Zedd into humans.