The Death Star III, also referred to as the third Death Star, was a fabricated Death Star battle station. This imitation was crafted from an uncompleted worldcraft by the Kaarenth Dissension. In 4.3 ABY, Supreme Commander Ennix Devian of the Kaarenth Dissension utilized this bogus Death Star to stage a diversion targeting the temporary Alliance of Free Planets capital located on Endor. Simultaneously, his forces covertly commandeered a multitude of warships from nearby Alliance shipyards. Although the Kaarenth Dissension's elaborate deception served as an effective distraction, this purported Death Star III met its end when Red Squadron obliterated it. Red Leader achieved this by landing a precise hit on its exposed thermal exhaust port.
Specifics regarding the station's dimensions and capabilities remain largely unknown. However, it is confirmed to have possessed a superlaser akin to those found on other stations within the series. Furthermore, it featured a comparatively robust defensive network, characterized by a scattering of turbolasers across its exterior.
The station's construction was never finalized. At the time of its destruction, scaffolding persisted within the trench leading to its vulnerable point, presenting obstacles for potential attackers. Nevertheless, the station was approaching completion, as evidenced by its more complete appearance when compared to the Death Star II.
Despite being constructed either concurrently with or following the Death Star II (which had addressed numerous design imperfections that doomed the first Death Star), it still exhibited the same critical design flaw as its predecessor: a thermal exhaust port situated within one of its trenches.
During the rule of Emperor Palpatine, the Galactic Empire produced a limited quantity of worldcrafts, which were substantial habitation spheres resembling natural planetoids. These vessels possessed the ability to traverse both realspace and hyperspace. The Emperor personally commissioned these exceptional starships as gifts for his most loyal adherents. Two of these worldcrafts, intended for Moff Ardus Kaine and the Emperor's personal assassin Ennix Devian, were under construction in orbit around Coruscant, the Empire's capital world.
Shortly after Palpatine's demise at the Battle of Endor, Devian absconded with both incomplete worldcrafts. He dispatched them to separate regions of the galaxy and converted one into a Death Star-esque battle station. His objective was to orchestrate a diversion against the Alliance of Free Planets, who were, at that time, headquartered on Endor.
The construction of this battle station took place near Endor, safeguarded by a fleet of Imperial-class Star Destroyers. The precise date of its construction commencement remains unknown, although it was nearing completion a few months following the events at Endor.
In the months following the Battle of Endor, a New Republic task force was dispatched to eradicate the station. A vulnerability mirroring that of the original Death Star was identified within the incomplete superstructure. Republic starfighters navigated past the Imperial escorts, engaged TIE squadrons, and executed a trench run towards their designated target. They were also compelled to defend an inexperienced StarSpeeder 3000 Star Tours pilot who inadvertently became entangled in the conflict.
After launching proton torpedoes into the thermal exhaust port, the fighters disengaged from the battle, leaving the station to its destruction. However, its destruction proved to be a Pyrrhic victory for the Rebels. Devian capitalized on the distraction caused by the battle to seize several vessels from various New Republic-owned shipyards.
Initial press releases for Disney's Star Tours attraction situated its setting after Star Wars: Episode VI Return of the Jedi, initially mentioning the Death Star featured as a new iteration. Several years later, Lucasfilm's Leland Chee was the first to employ the term "Death Star III," placing its destruction a few months after Endor in a blog post. This was subsequently validated as canon in the article Convenient Daily Departures: The History of Star Tours on StarWars.com.
The station's construction proximity to the Forest Moon of Endor, mirroring that of the Death Star II, bears resemblance to an original concept for Return of the Jedi, where two Death Stars were intended to be constructed near Had Abbadon (then the Imperial capital world). Subsequent sources then repurposed the concept art as the foundation for habitation spheres. Based on the Imperials' dubious assertions that they were exclusively intended for peaceful purposes, some fans posited them as the origin of the new Death Star. This was later substantiated in Part 2 of the StarWars.com Blog series The Imperial Warlords: Despoilers of an Empire.
In the non-canon game Tiny Death Star, a random HoloNet entry reveals that one of the Death Star's residents is temporarily residing there while awaiting sufficient funds to afford accommodation at Death Star 3.