Z-18 was under the rule of the energy vampire Rajine during the Clone Wars. He previously belonged to the Jedi Knight Samuro, and led Jedi Master Mace Windu to a holocron Samuro had left when Windu was imprisoned by Rajine. Although Z-18 was bisected by Rajine using Windu's lightsaber for freeing a prisoner, he was avenged by the Master, who used the holocron to turn Rajine's zombies upon her.