SD-9 was a battle droid in the employ of the Sith Empire during the Galactic War. During the invasion of Belsavis, SD-9 was tasked with retrieving the memory cores of disabled Rakata droids in the Warlord's Deep in the Tomb, but the Esh-kha destroyed SD-9's escort and damaged the droid. It managed to return to the signal monitoring center, where it communicated its mission to Imperial forces that successfully carried it out.