Advanced Combat Unit AZ-03

Advanced Combat Unit AZ-03 was a designation of several Battle droids used by Arlaia Zayzen, a gladiator in the Arena Grand of Zakuul. Along with other droids such as Medical Unit AZ-01, Combat Unit AZ-02, Assault Unit AZ-A and Assault Unit AZ-B, these droids were designated after Arlaia's own initials and assisted her during the fights. In 3632 BBY Arlaia was put up against a newcomer known as "the Mysterious Stranger", who defeated her, 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 along with Advanced Combat Unit AZ-03.

Behind the scenes
Several droids designated Advanced Combat Unit AZ-03 appear in Star Wars: The Old Republic: Knights of the Fallen Empire as part of the ninth boss fight of the "Eternal Championship".