Although droids were almost always subservient to carbon-based lifeforms, some were made to rule their own kind. The raspy-voiced EV-9D9, which worked in Jabba's headquarters, was a supervisor droid that took her job very, very seriously, to the point of outright cruelty.
EV-9D9 was Jabba's right-hand droid, lording over the other robots in her service. She directed their tasks and otherwise kept the place running as smoothly as possible. When droids failed to please her whims, she was apt to have them torn apart, piece by piece, in the most tortuous ways possible.
She didn't start out that way. EV-9D9 began her existence as a moisture vaporator technician. But she was reprogrammed in Mos Eisley, and she developed a mean streak that eventually found her delighting in the suffering of other droids.
Unlike most of the droids on this list, EV-9D9 had her brushes with fame in the movies. Fittingly, she threatens both C-3PO and R2-D2 with physical harm if they don't follow her directives. Her menacing voice and demeanor made this dominating droid one of the most memorable of our supporting cast of robot extras.