Grand Isle was an Imperial military installation situated on the planet Vladet, which served as the capital of the Rachuk sector. This base was constructed within the caldera of a dormant volcano. While it possessed shield generators and a pair of planetary ion cannons for defense, its antiquated geothermal energy source lacked the capacity to simultaneously power both the shields and the ion cannons. Aside from this, only four TIE/LN starfighters provided ground-based defense, making Grand Isle extremely dependent on the Rachuk Sector Fleet for its security.
Initially, the base was intended to deter piracy within the sector; however, it later functioned as the headquarters for Admiral Devlia, who commanded the Rachuk Sector Fleet. In the year 6.5 ABY, the New Republic launched an attack on Grand Isle as retaliation for a stormtrooper incursion that Devlia had dispatched against Rogue Squadron's base located on Talasea. The Y-wings belonging to Defender Wing penetrated the northern perimeter of Grand Isle's volcanic crater and obliterated the base utilizing proton torpedoes, resulting in Admiral Devlia's death.