J9-B4 was a J9 worker drone assigned to the New Republic CR90 corvette FarStar. Specifically tasked with maintaining the hydroponics bay, the unit—along with its two companions, J9-R1 and J9-K6-24—was considered a "busybody." A self-styled "efficiency expert," the droid had seemingly endless suggestions to improve crew morale and efficiency and bickered constantly with the other two J9 units on board.