The ThonBoka, alternatively referred to as the ThonBoka Nebula, was a nebula shaped like a sack located in the Centrality. It was filled with a mixture of gases, organic compounds, carapace-bearing creatures, and interstellar plankton. Its designation meant "StarCave Nebula" when translated into Basic. This nebula served as the native habitat for the Oswaft species, a race of sentient beings adapted to living in the vacuum of space, possessing the extraordinary innate capability to execute hyperspace jumps. The ThonBoka's remote location allowed the Oswaft to remain largely unknown until the Imperial Era. It was during this time that the Galactic Empire discovered their existence and perceived the pacifistic Oswaft as a potential danger. The Empire initiated a blockade of the ThonBoka in 3 BBY in an attempt to starve the Oswaft into submission, but ultimately, they were compelled to withdraw.
The ThonBoka nebula, which translates to "StarCave" in Galactic Basic, was a cloud of gas and dust in the shape of a sack. It measured approximately a dozen light-years across and was hidden in the distant Open Sea region of the Outer Rim's Centrality. Abundant with preorganic molecules and amino acids, the ThonBoka was inhabited by the sentient species known as the Oswaft, along with a multitude of native carapace-creatures and interstellar plankton, all drifting within the nebula's currents. The ThonBoka operated as an open system, facilitating the free passage of chemicals and nutrients via the interstellar tide, which was essential for the Oswaft's survival.
From the inside, the ThonBoka's gas and dust obscured the rest of the galaxy, creating the impression of being inside a massive cave. This cave-like feeling was amplified by the nebula's undulating shapes and folds, resembling geologic formations and limestone sheets. Entry into the nebula was possible only from one side, presenting a significant barrier, especially for the Oswaft. Their primary mode of long-distance travel was their natural ability to jump through hyperspace, but the gas and dust created too much friction. It was believed that Oswaft attempting to jump through the barrier would ignite and vanish. Three small, planetless stars, unusually close to each other at only one or two light-years apart, illuminated the ThonBoka from its central region.
During the Great Galactic War period, the nebula was the base of operations for a somewhat infamous group known as the Skyraiders of ThonBoka. However, by the time of the Imperial Period several thousand years later, the ThonBoka had faded into relative obscurity, inhabited only by the native Oswaft, who were virtually unknown to the wider galaxy. The Oswaft's existence had been known within the Centrality for centuries, but this knowledge was concealed from the Galactic Empire and the broader galactic community. It was not until 3 BBY, when an unusually curious young Oswaft named Lehesu decided to venture beyond his home's boundaries, that the Oswaft's existence became known outside the Centrality. Lehesu's explorations beyond his people's traditional territory sparked the Empire's suspicion and hostility. The Empire viewed the peaceful Oswaft as a potential threat due to their population size, physical magnitude, and unique ability to naturally jump through hyperspace. The Empire responded with a large force and besieged the ThonBoka, aiming to starve the Oswaft by disrupting the vital flow of nutrients.
The Oswaft were inherently pacifistic, and some were willing to accept the Empire's extermination rather than engage in combat. However, the deaths of Elder Bhoggihalysahonues and an Oswaft delegation during an attempt to negotiate with the invading fleet, as well as the encouragement of Human starship captain Lando Calrissian, who had befriended Lehesu during his travels beyond the ThonBoka, inspired the Oswaft to resist. The situation escalated into a violent battle between the Imperial forces, led by Sorcerer of Tund Rokur Gepta, and the Oswaft. The battle concluded with Gepta's death in a duel with Calrissian and the arrival of the Silentium, a droid civilization that had come to protect one of their own, Calrissian's companion Vuffi Raa. The Silentium's power was so imposing that it intimidated the Imperials into a quiet retreat, once again leaving the ThonBoka safe for the Oswaft.
Within the ThonBoka, where the native Oswaft freely navigated the cosmic currents, there existed only one artificial structure. This structure was the sole creation of the Oswaft throughout their history: the Cave of Elders. Constructed as an exact replica of the ThonBoka itself, the Cave of Elders—a rotating sphere composed entirely of precious gems—was located in the triangular plane formed by the three stars at the nebula's center. This site served as a significant meeting place for the Oswaft and was where the three Elders of their society governed their people.
The ThonBoka was the native habitat of the sentient Oswaft species, who regarded the isolated region as their sanctuary, a place of peace and abundance. The Oswaft felt connected to the nebula and could not imagine life beyond its borders. They lived in symbiosis with the ThonBoka, subsisting on the wildlife and debris carried by its currents. They remained ignorant of life beyond the nebula until 3 BBY. Despite the ThonBoka's vast size and the billions of Oswaft inhabiting it, they maintained a unified culture. Their ability to communicate telepathically over vast distances prevented the development of separate languages.
The ThonBoka served as the primary setting for Lando Calrissian and the Starcave of ThonBoka, authored by L. Neil Smith and published in 1983.