She nearly succeeded in taking over the starship but, fortunately, her plan failed when Wesley Crusher learned the truth about what she was up to and was able to reactivate Data – who had been disabled before the game was widely dispersed throughout the ship as the only person who would have been immune to its effects – allowing Data to restore the crew to their normal selves and allowing them to capture her vessel. (TNG: "The Game")
According to the final draft of the script, Etana was "alien, gorgeous, with a full, flowing mane of hair;" additionally, the script also indicated that her last name was Jol.
The character was never specifically identified as Ktarian in the episode, where Etana only spoke of the Ktarians in third person. But Etana is identified as Ktarian in reference and background materials, including Star Trek: Aliens & Artifacts (p. 117), Star Trek Encyclopedia (3rd ed., p. 223), and StarTrek.com. 
For more information on the discrepancies associated with Ktarians, see the full analysis at Ex Astris Scientia.
According to the Star Trek: The Next Generation - Player's Guide, Etana Jol turned herself in to Ktarian authorities and agreed to testify against her superiors in exchange for immunity. Afterwards, she became the public relations officer for a chain of Ktarian resorts, but there are rumors that she's planning to embark on a political career.