Viper was a group of three CR90 corvettes that served in the Imperial Navy during the Galactic Civil War. After the Imperial-class Star Destroyer Intrepid's hyperdrive was damaged in an accidental collision with an EF76 Nebulon-B escort frigate, leaving it stranded in the Circarpous system, Viper group was sent, along with several Assault Gunboats to reinforce it. After the Battle of Yavin a group of corvettes named Viper came across the Frigate Anvil being evacuated. Keyan Farlander managed to destroy them.