The franchise, which began with the 1977 film Star Wars, features a variety of droids designed to perform specific functions.
Protocol droid
A protocol droid specializes in translation, etiquette and cultural customs, and is typically humanoid in appearance. The most notable example is C-3PO, introduced in Star Wars and featured in all sequels and prequels. 4-LOM is a protocol droid turned bounty hunter who responds to Darth Vader's call to capture the Millennium Falcon in The Empire Strikes Back. TC-14 is a droid with feminine programming that appears in ', and ME-8D9 is an "ancient protocol droid of unknown manufacture" that resides and works as a translator at Maz Kanata’s castle on Takodana in the 2015 '.
Astromech droid
An astromech droid is one of a series of "versatile utility robots generally used for the maintenance and repair of starships and related technology". These small droids usually possess "a variety of tool-tipped appendages that are stowed in recessed compartments". R2-D2 is an astromech droid introduced in 1977's Star Wars and featured in all subsequent films. The malfunctioning droid R5-D4 also makes a brief appearance in Star Wars. U9-C4 is a timid droid sent on a mission with D-Squad, an all-droid special unit in , C1-10P is an oft-repaired, "outmoded" astromech who is one of the Star Wars Rebels regular characters, and BB-8 is the astromech droid of X-wing fighter pilot Poe Dameron in The Force Awakens.
Battle droid
A battle droid is a class of military robot used as an easily controlled alternative to human soldiers, most notably seen in the Star Wars prequel trilogy of films and the ' TV series, in which 'B1' and 'B2' models are frequent antagonists. Due to their ubiquity, the terms 'B1' and 'battle droid' are used interchangeably; 'B2' models are also referred to as 'super' battle droids. The droids are mainly used as the military force of the Seperatist alliance of the Confederacy of Independent Systems, as an alternative to the Clone army used by their rival, the Galactic Republic. The tall, thin B1 model resembles the Geonosian species, who designed the droids, and are known to "suffer programming glitches that manifest as personality quirks." The droideka is a three-legged heavy infantry unit with twin blasters and the ability to generate a force shield and transform into a disk shape. Multiple other types of specialized battle droids have been featured in the Star Wars fictional universe. Within the Star Wars Legends continuity, HK-47 is a humanoid soldier robot, designed as a violent killer, which first appeared in the 2003 video game'.
Other droids
During the production of The Empire Strikes Back, Joe Johnston drew storyboard panels influenced by Dan O'Bannon and Moebius's short comic "The Long Tomorrow", one of which repurposes a pose Johnston admitted he borrowed from said work. The same panel of the comic features a robot design by Moebius, which may have been the basis of the probe droid design that concept designers Johnston and Ralph McQuarrie created for the film. Star Wars: The Clone Wars has featured WAC-47, a "pit droid" programmed as a pilot and sent on a mission with the all-droid special unit D-Squad, and AZI-3, a medical droid serving the cloners of Kamino who helps uncover the secret of Order 66. The 2015 young adult novel by Cecil Castellucci and Jason Fry introduces the droid PZ-4CO, to whom Leia Organa dictates her memoirs. PZ-4CO also appears in The Force Awakens. In the 2016 filmRogue One, K-2SO is an Imperial enforcer droid reprogrammed by the Rebel Alliance.
