Seelos, situated within the Kwymar sector of the Outer Rim Territories, was a desolate planet characterized by desert landscapes. It resided in the star system of the same name. While initially considered for potential mining operations, by the time of the Age of the Empire, all efforts towards establishing settlements and resource extraction had ceased. This abandonment was partly attributed to the presence of lethal joopa worms dwelling beneath the extensive salt plains. For the most part, Seelos was unpopulated, except for scattered outlaw communities nestled at the base of the mountains, and the retired clone troopers named Rex, Wolffe, and Gregor.
Within the Outer Rim's distant Kwymar sector, the Seelos system contained the desert planet of Seelos. Its terrain was defined by vast salt flats and arid expanses, broken up by ranges of blue mountains rich with valuable minerals such as copper. The planet was inhabited by large, armored, worm-like beings referred to as joopas, which were deemed hazardous and generally avoided by the planet's few inhabitants. The danger presented by the joopas also hindered attempts to extract resources from the planet's mountains.
Rather than established communities or organized settlements, Seelos primarily featured a few outlaw towns that served as refuge for outcasts, including criminals and marked men. Outside of these towns, such individuals made their homes in various hidden locations, shelters, and camps within the mountains, providing protection from both joopa attacks and the pursuit of bounty hunters.
Sometime before 4 BBY, there were attempts to exploit the valuable resources found within the planet's mountains by mining companies. However, these efforts were quickly abandoned due to the lethal attacks by joopas, which rendered further operations untenable. The Galactic Empire regarded Seelos as a deserted world, inhabited only by criminals and the bounty hunters in pursuit of them.
Following the Clone Wars, Seelos became the chosen home for several veterans of the Republic clone troopers: Captain Rex along with Commanders Wolffe and Gregor. These former soldiers resided in a repurposed AT-TE walker from the Grand Army of the Republic, which they used as a fishing vessel for hunting joopa. They primarily hunted to sustain themselves, but they also bartered surplus joopa meat and plating with the outlaw settlements to maintain the operational status of their walker.