Separatist Droid Army/Legends

The Droid Army was created by the Confederacy of Independent Systems, in an effort to secure power throughout the Galaxy. It consisted of quintillions of battle droids. An army the size of the Droid Army had never been seen before, until the Clone Wars and the creation of the Army of the Republic. Seemingly defeated by the Galactic Republic numerous times (including the Battle of Naboo), the Droid Army continued to grow in strength and size. Count Dooku the nominal leader of the Seperatists, almost secured a victory on Geonosis using battle droids, Super battle droids, and Droidekas, but victory was snatched from the jaws of defeat thanks the the appearance of the Army of the Republic.

With the deaths of Count Dooku, General Grievous, and the Separatist Council (including Neimoidian Nute Gunray), the Droid Army was forced to shut down by Darth Vader, by order of Emperor Palpatine.