BO-55 was a Astromech droid of a discountinued model that was picked up by Ravagers pirate Torque, who rebuild and reprogrammed him into a blood-thirst killing machine. BO-55 eventually convinced the pirates to oversee the construction of Blaster, a jury-rigged battle droid, to serve as his companion in battle. In 3638 BBY the Ravagers Captain Coratanni dispatched them to take out the strike team send by her predecessor Ruugar. BO-55 and Blaster engaged the "dunderheads" on the deck of the Soaring Duros, but were defeated after a prolonged fight.