Taiyou no Shisha Tetsujin 28-gou

A pre-teen boy named Shoutarou Kaneda inherits a 60-foot-tall, 50-ton remote-controlled robot left by his late father. He takes on the responsibility of operating the machine, known as Tetsujin, to fulfill his father's mission of fighting evil and maintaining peace. As the youngest Interpol agent, Shoutarou pilots the robot in battles against various threats, including mad scientists, pirates, ninjas, and international criminals, each wielding their own large machines. His mentors include Dr. Shikishima, a colleague of his father, and Inspector Ohtsuka, the Interpol liaison. Shoutarou's most significant challenge comes in the form of the Space Demon King, an alien antagonist capable of threatening the entire Solar System.