The Emerald Empress
Sarya, the outlaw ruler of the planet Vengar.
The Emerald Empress possesses the Emerald Eye of Ekron, a floating sphere with "nearly unlimited power" that she discovers hidden in crypt built by "the long-dead Ekron civilization" and uses to make herself a tyrant. Exiled after her subjects rebel, the Empress becomes a criminal to raise an army and return home. She eventually is recruited by the Legion of Super-Heroes to battle the Sun-Eater and as a consequence of meeting several other criminals during this endeavour, becomes a founding member of the Fatal Five (Adv No.352-353: "The Fatal Five, Parts I-III: To Save a Galaxy; An S.O.S. to Evil; and Slain by the Sun-Eater").
Despite an initial attraction to Superboy, the Emerald Empress is a sworn enemy of the Legion.