The network of defense towers saw action in 4000 BBY, during the Battle of Iziz, where they were employed against the Beast Riders from Onderon's wilderness. These emplacements were subsequently destroyed, when Iziz was virtually leveled after the battle. However, they would be replaced some fifty years later by a network of air defense towers. The new defensive network would see action during the Onderon Civil War, when the Jedi Exile returned to that world to help Queen Talia fend off the Sith-backed coup d'état staged by her cousin, General Vaklu.