Gigantor

Plot
During the final days of World War II, the Japanese military is secretly developing a superweapon intended to help save their nation. After twenty-seven failed attempts, Dr. Kaneda completes a three-story high, remote-controlled robot officially named Tetsujin 28-go.The robot is completed after the war ends, however, and Dr. Kaneda dies of heart failure shortly after completing Tetsujin 28.

Rather than becoming the military's key weapon, Tetsujin 28 is given to Dr. Kaneda's ten-year-old son, Shotaro, and, under his control, the robot is put to work stopping criminals and enemy robots.