Haroon served as the singular moon orbiting Despayre, a penal world under the Imperial regime, situated within the Horuz system of the Outer Rim's Atrivis sector. Following the relocation of the partially-built Death Star superweapon into orbit around Despayre, the Galactic Empire began to exploit the crystalline surface of this moon. A compact mining facility was established on Haroon, dedicated to extracting exceptionally large, meticulously cut crystals intended for use in the Death Star's construction. Approaching its completion in 0 BBY, the Death Star destroyed Despayre through a three-stage test firing of its superlaser, obliterating the planet into a field of debris, which presumably engulfed Haroon during the event.
Initially, Haroon's visual representation was limited to a satellite circling Despayre in a cinematic from the 1993 video game Star Wars: X-Wing, illustrating Despayre's annihilation by the Death Star's superlaser. LucasArts was developing Haroon extensively for Star Wars: The Force Unleashed, initially conceiving it as a completely original planet. The concept envisioned a verdant, crystal-rich world where the Empire mined resources for the Death Star's massive focusing lenses. Greg Knight produced at least two pieces of concept art for Haroon, portraying a scene where the incomplete Death Star fired upon the planet's crystal-laden surface.
The March 2007 edition of Game Informer magazine was the first to announce Haroon's inclusion as a playable location in The Force Unleashed; by this point, it was designated as a moon. The game's protagonist, Darth Vader's secret apprentice, was intended to travel there to liberate Gial Ackbar, a Mon Calamari who had been condemned to lifetime servitude in Haroon's mines. However, complications arose when it became apparent that Ackbar's rescue from Imperial captivity and subsequent induction into the Rebel Alliance were already established in other sources, conflicting with the developers' narrative plans. Consequently, Haroon was cut from the game and replaced by the more recognizable Cloud City from Star Wars: Episode V The Empire Strikes Back.
Despite this, Haroon eventually achieved some form of canon recognition. In 2008, The Force Unleashed Campaign Guide officially identified Haroon as Despayre's moon, incorporating elements from the game's conceptual stages, such as its crystalline composition and the Imperial mining operations underway. In 2009, The Essential Atlas also made reference to Haroon, and an image of the moon was included in an illustration of Despayre's destruction by Chris Trevas.
Although Haroon was initially envisioned as a green world during the conceptualization of The Force Unleashed, X-wing depicts the moon as being purple in color, and the illustration in The Essential Atlas shows the moon illuminated by Despayre's destruction, leaving its true coloration ambiguous. While no source has definitively confirmed whether Haroon was destroyed alongside Despayre, the moon is no longer visible following Despayre's annihilation by the Death Star in the X-wing cutscene.