Robotic Unit 41942008241283 (often called RU) is Zark's robotic servant. RU quit his job when Zark was revealed as Zxaro.
RU was made long ago by Zark to destroy The Boy. RU did nothing and shut down. RU was then locked away behind a door. Years later, The Boy unlocks and opens the door, finding RU. After RU sees Zark was actually Zxaro, he (RU) quit his job.