Lol technically speaking, the CIS was actually defeated by the Republic. However, a splinter group of Geonosians managed to not only rebuild a tiny group of battle droids on the volcanic planet Mustafar, but also had plans to make effectively what you would call ultra battle droids; they were to be much stronger than even super battle droids :D But the Empire (newly fledged, as of the campaign mission on SW:BF II) put a stop to that by calling an orbital bombardment on the facility, and destroyed the battle droids as well as the plans for more. the head Geonosian was killed in battle prior.