Emerald Empress

Emerald Empress is a fictional supervillain in DC Comics. An enemy of the Legion of Super-Heroes and a member of the Fatal Five, she was created by Jim Shooter and Curt Swan, and first appeared in Adventure Comics #352 (January 1967)

Sarya of the planet Venegar (referred to simply as 'the Empress') was recruited by Superboy and the Legion to combat the menace of the Sun-Eater. Once the Sun-Eater was defeated, she joined the Fatal Five with Tharok, Validus, Mano and the Persuader.[3]

The Empress had no innate super-powers; rather, she employed a powerful mystical item called the Emerald Eye of Ekron, an approximately 2' diameter sphere that obeyed her mental commands.[4] The Eye could fly and emit blasts of energy, and allowed the Empress to fly as well as survive in space. The Eye's residual energy also gave her, on at least one occasion, super-strength. It caused her to grow to gigantic stature during one battle. The Eye could also reform itself if shattered.

Sarya with the Eye of Ekron in Supergirl vol 7 #12. Art by Robson Rocha.
The Eye is an item of immense power; it defeated Superboy directly more than once, though it seemed to have more trouble with Mon-El, perhaps because he was immune to green Kryptonite and its blasts may have contained elements of it. Despite this, for unknown reasons, the Eye does not like green Kryptonite, and being exposed to a chunk of it has made the Eye flee on more than one occasion (leaving the Empress behind temporarily).

The Emerald Empress died when, at her request, Legionnaire Sensor Girl used her powers of illusion to mask Sarya's presence from the Emerald Eye of Ekron. As the Empress' body quickly withered and decomposed, she expressed relief to be free from the Eye's control, indicating both that their symbiotic relationship was unwilling and that the Empress was far older than she appeared