A celestial body was the homeworld and point of origin of the Grysk warlike species, which at one point formed the Grysk Hegemony. The Grysks sought to conquer the Unknown Regions and the surroundings of their point of origin, as well as the Chiss Ascendancy nation. Around 18 BBY, a Grysk fleet was destroyed by Chiss Senior Captain Mitth'raw'nuruodo, who led a mission to the edge of the Unknown Regions to find the Grysks' location after the destruction of the fleet. However, he found no clue of their whereabouts.
The senior captain was exiled for his actions during the battle against the Grysk fleet, and joined the Galactic Empire, becoming a Grand Admiral. Thrawn attempted to find the celestial body while fighting Grysk forces between 2 and 1 BBY; however, he was unsuccessful, and while Ascendancy Admiral Ar'alani dealt a major blow to the Hegemony, the Grysk homeworld was not found.
The Grysk homeworld was a celestial body located deep in the Unknown Regions, Chiss Grand Admiral Mitth'raw'nuruodo also known by his core name "Thrawn" presumed it was not too deep in Regions, as it was thought that the Grysks' main center of power would be a considerable distance away from their operations in the Galactic Empire's territory outside of the Unknown Regions.
Grand Admiral Thrawn
The Grysk Hegemony, the nation of the Grysk warlike species, sought to conquer the region of the Unknown Regions surrounding the Grysk celestial body and also operated in the Empire's territory. During the conflict between the Empire and the Hegemony, Thrawn, who had been exiled from the Chiss Ascendancy after he defeated a Grysk fleet in a battle above the Unknown Regions planet Sunrise, attempted to find the homeworld in the edge of the Unknown Regions, but was unsuccesful.
After joining the Empire and becoming a grand admiral, he hoped to find the homeworld's location by studying Grysk artwork, presuming that the Grysk base was relatively far away from the Outer Rim Territories planet Mokivj, intending to subsequently eliminate the Grysks' threat to the Ascendancy and the Empire when he found it.
In 2 BBY, Thrawn and the Dark Lord of the Sith Darth Vader came across Grysk forces on Mokivj and fought them in several skirmishes both there and elsewhere in the galaxy while looking for the Grysk homeworld. Although Thrawn did not locate the world, Chiss Admiral Ar'alani ultimately delivered a decisive blow to the Hegemony.
The homweorld was the home of the Grysk species and the Grysk Hegemony, the nation of the warlike species.
The homeworld was mentioned in the 2018 novel Thrawn: Alliances, the second entry in the Star Wars: Thrawn novel series authored by Timothy Zahn.