The individual who falsely represented himself as the Galactic Republic Jedi Master Obi-Wan Kenobi was actually a Galactic Empire thespian. He was surgically altered by cosmetic surgeons to visually mimic Obi-Wan Kenobi, all at the command of Darth Vader.
Darth Vader, the Dark Lord of the Sith, recruited an unnamed performer and arranged for him to have plastic surgery so that he would resemble Kenobi. Furthermore, he was given technological enhancements designed to simulate Force abilities, thereby enhancing the illusion beyond mere physical appearance.
This impersonator made his appearance on the desert planet of Aridus, located in the Expansion Region. There, he gained the friendship of the native reptilian Chubbits—who had long been victims of Imperial mistreatment—and assumed a leading position in their rebellion against the local Imperial forces. Hovertrains were targeted in ambushes, and Imperial Military as well as mining facilities were attacked. During one particular skirmish, the fabricated Kenobi rescued a Rebel Alliance operative from capture by Imperial soldiers.
News of this rescue reached the rebel base situated on the jungle moon of Yavin 4, which at the time was under siege by an Imperial fleet. Luke Skywalker, a young rebel pilot who had observed the death of his mentor on the first Death Star during a confrontation with Darth Vader, became intrigued by this supposed reappearance and set out for Aridus with C-3PO aboard his Rebel smuggling ship.
Upon arriving on Aridus, they came across a group of poorly armed Chubbits assaulting a heavily fortified Imperial hovertrain. Witnessing his fellow Rebels in peril, Luke and C-3PO launched two bags containing proton charges from their transport towards the hovertrain, resulting in its destruction. However, due to their proximity to the train, flying debris struck Skywalker, causing him to lose consciousness. Fortunately, the Kenobi impersonator—who was leading the Chubbits—arrived and provided assistance to Skywalker.
Skywalker was fortunate to have suffered only a minor concussion from the impact of the debris. After a quick recovery, he and his droid joined forces with the Chubbits and the individual he believed to be Kenobi, unaware of the deception. Subsequently, they continued their journey across the Aridus deserts on a locally manufactured wind-runner.
The Chubbit rebels intensified their insurgency against the Empire, attacking and obliterating an Imperial outpost. The Kenobi imposter, employing technological tricks to compensate for his lack of Force abilities, gained the respect of both the Chubbits and Luke Skywalker. Following the raid, the Kenobi impersonator communicated with Darth Vader himself via a holoprojector. He informed his master that the plan was unfolding as intended and that Skywalker had joined him, still unaware of the deception. As part of the scheme, the imposter was to guide Luke to the Iron Tower where Vader would be waiting, thus making Skywalker a prisoner of the Sith Lord.
However, the impersonator began to experience misgivings about his assigned task. The respect he received from the Chubbits and the admiration in Skywalker's gaze made him realize that Obi-Wan Kenobi was a truly great Jedi Master, while he himself was merely a spineless actor willing to serve the oppressive, Sith-controlled Galactic Empire.
Later, he and Skywalker, riding their Droffi steeds, set out alone for the Iron Tower on a mission to destroy the automated power transformer and signal amplifier whose powerful ultra-strong frequency waves were crippling the nervous systems of the Chubbits. En route, their Chubbit allies overcame an Imperial patrol speeder.
Upon reaching the Iron Tower, the two separated as Vader had planned. The Dark Lord of the Sith contacted the Kenobi impersonator and commanded him to lure Skywalker into his trap. However, having now seen the Empire's true nature, he defied Vader's orders. In response, the Sith Lord used the Force to hurl equipment at the impersonator with fatal force.
The impersonator understood that this attack would cause Skywalker to sense Vader's presence within the Tower, thereby jeopardizing the Dark Lord's plan. As soon as Vader departed to intercept Skywalker, the impersonator activated an emergency beacon, alerting C-3PO aboard the Rebel ship to Skywalker's location. He also activated a control lever that initiated a power overload in the Tower's upper levels, resulting in its destruction, nearly killing Vader, and effectively shutting down the majority of Imperial operations on the planet.
The impersonator knew that Skywalker would survive the explosion, and the boy soon rushed to his side as he lay dying. With his last breaths, he confessed to Skywalker that he was merely an impostor, even pondering how well he had played the role.