Operation: Counterstrike was a military endeavor undertaken by the Republic Defense Coalition alongside the Jedi Order during the High Republic Era. Its purpose was to fight the lawless marauders known as the Nihil, acting as a counter-piracy initiative. This operation was spurred by the Nihil's destructive raid targeting the Valo Republic Fair, coupled with the Jedi's victory against the Drengir during the defeat of the Drengir. Jedi Master Avar Kriss took the lead in directing the operation. Jedi Knight Keeve Trennis initially considered calling the operation the crusade against the Nihil, but she quickly changed her mind, viewing it instead as a necessary reaction to the danger they posed.
After three months of Operation: Counterstrike, the Republic and the Jedi had achieved considerable success. They had confronted the Nihil in multiple locations, such as Carlac, Magaveene, and the Dreighton Nebula. As a result, the Nihil's forces were significantly weakened, forcing them to disperse. Nevertheless, Marchion Ro, the elusive Eye of the Nihil, orchestrated a wave of unexpected assaults by the Nihil to overextend the Republic's resources, ultimately enabling the Nihil to bring down the Starlight Beacon.