Kylee is a human magnet. She can attract metal objects and climb up metal walls.
Kylee has been with Hatch for an unknown amount of time. Tara is her best (and only) friend. She is jealous of Taylor at the beginning of Prisoner Of Cell 25, because she was getting more attention from her, but this jealously has probably ceased due to Taylor leaving the Elgen for the Electroclan. In Rise of the Elgen, Kylee is relocated to Peru with the rest of the Elgen kids. She mentions Zeus's name on their tour of the facility, (which had been forbidden by Hatch). This action results in Kylee being given 'Punishment B' : being locked in her room on a strict bread and water diet for a week, while being forced to write I will not disobey Dr. Hatch ten thousand times.
During Storm of Lightning after Quentin decides to overthrow Hatch and take control of the Elgen, Kylee joins Quentin. After Hatch finally finds out about Quentin's betrayal and planned mutiny, he has all 5 Elgen Glows, including Kylee, arrested and imprisoned.
During Fall Of Hades Kylee doesn't actually appear in the book, but it's mentioned that she's imprisoned in the Elgen Kremlin. Kylee betrays Quentin and rejoins Hatch. Unlike Quentin, Torstyn, and Tara, Kylee's currently scheduled to be released.