Kikaider-01: The Animation

Though Jiro has put a stop to the evil organization Dark, a new threat awaits him: Shadow, a group of robots who are hell-bent on kidnapping Professor Gill's child, Akira, who is now in the care of Jiro. Along with Akira's protector, Rieko, Jiro must now protect the boy from Shadow - but he has help. Professor Komyouji had built a prototype known as Akira (when transformed, Zero-One), and together the two brothers may just be enough to stop the forces of Shadow for good.