Fest was a planet of mountains and cold, found in the Outer Rim Territories. It served as the adopted homeworld for Kassa, a boy who would later be known as Cassian Jeron Andor, and who was forged into a rebel. Human inhabitants of Fest were forced into labor in the industrial sectors after the Galactic Empire took control. Eventually, the Empire devastated the world, leading to an influx of refugees who were welcomed at the Rebel Alliance base located on the moon of Yavin 4.
Situated where the Outer Rim Territories and the New Territories meet, Fest was a planet connected to Dantooine via a hyperspace route. Its defining features included its mountainous terrain and cold climate.
Well before 22 BBY, during the final years of the Galactic Republic, Maarva Andor and Clem Andor, working as scavengers, rescued the boy Kassa from his homeworld of Kenari, fearing the Republic would massacre his tribe. Maarva raised him as "Cassian Jeron Andor," and made sure to list Fest as his homeworld on every official record. As the Clone Wars concluded, spanning from 22 BBY to 19 BBY, the Republic became the Galactic Empire. This new government seized Fest's industrial areas, forcing many human residents to work there.
In 5 BBY, Andor murdered two sentry guards belonging to the Pre-Mor Authority Security Forces on Morlana One. Prior to this, Andor had mistakenly told a local hostess that he was from Kenari, which led to Pre-Mor Enforcement getting the information. When the authority received a tip that Andor was the Kenari male suspect, some officers became suspicious when they looked at Andor's file and saw that Fest was listed as his homeworld. Nevertheless, the hostess was brought in and identified Andor as the killer.
Despite the Imperial presence, Fest became a secret operations center for an organized rebellion secretly controlled by Senator Mon Mothma by 2 BBY. As a result, the world was marked on a map of the galaxy sent to Mothma, which showed rebel safe worlds, starfighter hubs at level five or higher, operations headquarters, shadow planets, and hidden deep space caches. Archivist Hendri Underholt put the map into the non-electronic archive called The Rebel Files. The rebellion was formalized as the Rebel Alliance in 2 BBY, and Fest suffered greatly under Imperial rule, causing refugees to seek sanctuary at the Alliance base on Yavin 4's moon.
Fest's introduction to Star Wars canon occurred with simultaneous mentions in Star Wars: Rogue One: Secret Mission, a young-readers book by Jason Fry, and Star Wars: Rogue One: The Ultimate Visual Guide, a reference book by Pablo Hidalgo, both of which were released on December 16, 2016. The planet Fest first appeared in the Star Wars Legends continuity in The Rebel Alliance Sourcebook by West End Games, written by Paul Murphy and published in 1990 as part of Star Wars: The Roleplaying Game. The world was illustrated by artist Allen Nunis in that sourcebook. Fest's initial appearance in Legends was in the 1995 video game Star Wars: Dark Forces, which was developed by LucasArts.
The books Star Wars: Rogue One: Secret Mission and Star Wars: Rogue One: The Ultimate Visual Guide stated that Cassian Andor was from Fest. Later sources repeated this information; however, the second episode of Tony Gilroy's live-action Disney+ series Andor, "That Would Be Me" from the first season and released on September 21, 2022, revealed that this was a fabrication by Maarva Andor, and that Cassian was actually from Kenari. Gilroy stated at a panel on the first day of Celebration Europe on April 7, 2023, that he chose to "turn [it] upside down" when creating a homeworld for Andor after seeing the existing information about Fest. The 2023 reference book Star Wars: Timelines incorrectly states that Andor was from Fest as if it were fact.