Magnerobo Ga-Keen (1976)

Original title: マグネロボ ガ・キーン

Evil space creatures retreat from the treacherous Ice Age and hibernate on the ocean floor. They awaken millions of years later to conquer Earth! Only the ingenuity and resources of Sir Miles and his awesome robot creations have a chance at defeating them! He enlists world karate champion Janis to pilot the robot Magnon, and his daughter Lady Ester Nevers, to pilot Magneta. When Janis and Lady Ester unite the two Robots, Magnon and Magneta are transformed into Magnos, the ultimate power robot! Will the might of the malevolent space aliens defeat Magnos? Or, will Magnos triumph over the evil forces and protect Earth's freedom against future invaders? As suspense mounts, you'll discover what happens in this exciting adventure of humans and machines good versus evil!