During the Clone Wars, Z-18 was controlled by the energy vampire named Rajine. Formerly, he was the property of the Jedi Knight called Samuro. He guided Jedi Master Mace Windu to a holocron that Samuro had hidden when Windu was incarcerated by Rajine. Rajine cleaved Z-18 in two with Windu's lightsaber for the droid's act of liberating a captive. However, the Master retaliated for this deed by using the holocron to turn Rajine's zombies against her.