Antipose XII, a planet situated in the Outer Rim Territories, was found within the Centrality sector. This planet was characterized by violet skies, and its indigenous population used "dubesor" as a derogatory term. The luxury yacht named Arleen offered year-long excursions from the Oseon system to both Antipose XII and the nearby celestial body Antipose IX. The gambler and freighter captain Lando Calrissian once used "dubesor" as a predetermined password, which caused him to ponder what the inhabitants of Antipose XII were doing during that particular night.
Antipose XII, a terrestrial planet, held the twelfth orbital position around the star within the Antipose system. This system was located in the Centrality sector, which itself was a part of the Slice region of the Outer Rim Territories. Like the rest of the system, Antipose XII was linked to the Falko and Paulking systems via the Falko Run hyperlane. Its skies were famously known as "the most violet skies in the universe."
The yacht Arleen, which was built by 3 BBY, conducted year-long voyages from the Oseon system to Antipose IX as well as Antipose XII. Sometime between 3 BBY and 2 BBY, Lando Calrissian, the gambler and freighter captain, was compelled to journey to Oseon 5792, a heavily guarded asteroid that served as the private residence of the wealthy Bohhuah Mutdah. Calrissian was provided with a secret password, "dubesor," an offensive term used by the people of Antipose XII, to gain access to the asteroid. He later learned the meaning behind the word. The captain shared this information with Vuffi Raa, his droid copilot, as Vuffi Raa was relaying the password to a picket ship that had intercepted their vessel near Oseon 5792.
After they were given instructions for landing the Millennium Falcon, their light freighter starship, on the asteroid, Calrissian wondered if the natives of Antipose XII were loudly celebrating in a local saloon that night and calling each other "dubesor." The gambler thought to himself that such a scenario would be preferable to his upcoming mission, which involved smuggling two law enforcement officers onto Oseon 5792 to arrest Mutdah for trafficking and using illegal narcotics.
The residents of Antipose XII, who were few in number, incorporated the native slang insult "dubesor" into their lexicon.
Antipose XII was initially mentioned in Lando Calrissian and the Flamewind of Oseon, which was published in 1983 as the second book in The Lando Calrissian Adventures trilogy by L. Neil Smith. The roleplaying game source article "Twinkle, Twinkle Little Star, How I Wonder Where We Are," featured in the thirteenth issue of Voyages SF magazine in 1990, placed the Antipose system, and therefore Antipose XII, within the Seswenna sector. Because this article was published independently of Lucas Licensing, its canonicity within the Star Wars Legends continuity was never officially established. Furthermore, the name of Antipose XII was incorrectly spelled as "Antipose XI" in "Twinkle, Twinkle Little Star, How I Wonder Where We Are."
The Complete Star Wars Encyclopedia, which was released in 2008, also created a potential inconsistency by stating that the Antipose system, including Antipose XII, was located "not far from Centrality." This contradicted the roleplaying game source article "A Campaign Guide to the Centrality" by Michael Kogge, which was published in the fifth issue of the Star Wars Gamer magazine on July 24, 2001. This article had previously established that the system was indeed a part of the sector. The Essential Atlas, a reference book published in 2009, later superseded both the Voyages SF 13 placement and the information from The Complete Star Wars Encyclopedia by placing the Antipose system in grid square U-8 as a component of the Centrality.