Dr.Macerena had created the MegaRobot based on his obsession on mechanics
Well the MegaRobot had been made to save the Sleepcity from dangerous villains but One day when the MegaRobot was getting prepared for another fight with the villains it was going to be a hard task preparing it for doing it. Because it was damaged from its mechanical brain making it malfunction.
Its making its fate to become a hero to the greatest villain because of its overpowered abilities and weapons.