Arlaia Zayzen was a female Human living during the Galactic War. By 3632 BBY she became known as the gladiator in the Arena Grand of Zakuul under the title "Master of Killers". During the fights in the Arena, she used multiple droid assistants, such as Medical Unit AZ-01, Combat Unit AZ-02, Advanced Combat Unit AZ-03, Assault Unit AZ-A and Assault Unit AZ-B. That year, Arlaia was put up against a newcomer known as "the Mysterious Stranger", who defeated her in the first round of the Arena fights. She sustained serious injuried and while on the brink of death, her mind was downloaded into an Isotope-5 droid called the "Doom Droid". With a new, completely robotic body, Arlaia tried to claim her revenge against the Stranger, but was defeated in round nine of the Arena fights.