B1 battle droids were battle droids that made up the backbone of the Trade Federation Droid Army and the Separatist Droid Army. It was the successor of the hunter-killer droid. B1s were perhaps the most numerous—and expendable—soldiers in galactic history, and, unlike most organic soldiers, they were capable of action in hostile environments like underwater or in space. They were designed, for the most part, to defeat their enemies through sheer numbers, not through their ability to think and utilize combat skills.