The droid marine represents a specific model within the B1-Series battle droid line. These droids were utilized by the Confederacy of Independent Systems throughout the duration of the Clone Wars.
These droid marines, like all combat units engineered by Baktoid Combat Automata, were primarily intended for combat against the forces of the Republic Navy. Identifiable by their green markings on their skeletal frames, these droid marines were armed with a standard battle droid E-5 blaster rifle, an E-60R missile launcher, and four thermal detonators. They also carried a "backpack" like object with them, similar to their B1 counterparts. While possessing the capability to pilot spacecraft, their main duties involved defending capital ship or infiltrating and attacking enemy vessels. Sightings of them on planetary surfaces were rare.
Serving as the final defensive line for Separatist capital ships against clone boarders, they also proved valuable in boarding Republic's Venator-class Star Destroyers with the intent of destruction from within. They would infiltrate the internal systems of a Republic warship and detonate the shield generator, thus enabling a CIS cruiser to destroy the star destroyer. Droid marines demonstrated their potential as formidable adversaries against the Clone marines and Pilots of the Clone Army. Their boarding tactics included landing within the hangar bays of enemy cruisers. Following the execution of the Separatist Council, these units were deactivated. Nevertheless, some were subsequently employed by the Separatist fugitive Gizor Dellso during the Battle of Mustafar.