Ken Ishikawa

When a UFO appears over Japan, both the heroes of Great Mazinger and Getter Robo want to investigate it first, out of a sense of rivalry. Getter finds it first since the Mazinger robot is being repaired. However they are unable to defeat the apparently living vehicle. It had already dropped a metal-eating monster on Japan named Gilgilgan and Great Mazinger confronts it only to be badly beaten. (wikipedia)

When earthquakes shake up Japan, Professor Saotome is certain that it is the work of the Dinosaur Empire. Michiru goes out to investigate in the Command Module but is quickly shot down and injured; the culprit is none other than Megazaus! Team Getter Robo is eager to get revenge for Michiru, but first they have to brave the fractured roads and find a physician for her. Once Getter Robo is formed, they must track Megazaus underground and defeat him before he destroys the cities of Japan. (myanimelist.net)

Humanity is under attack by demonic creatures called Oni. Unable to fight back by any other means, the scientist Dr. Saotome creates a series of giant robots that harness the mysterious power of Getter Rays, giving them the strength necessary to fight the Oni. The strongest of these is Getter Robo, and Saotome must enlist three very different men to pilot it - martial artist Ryoma Nagare, criminal leader Hayato Jin, and monk Benkei Musashibou. (myanimelist.net)

13 scientists seek to tap genetic powers by creating a hybrid of man and beast. Years later, 13 of their children are embroiled in a battle to undo their handiwork, while Shinichi, the son of one of the scientists, teams up with Christian super-beings to save the world. (myanimelist.net)

An entire city is destroyed by two monstrous and omnipotent beings. Genzou Kuruma, a scientist but also the leader of a sect wishes to awake God, but first, he needs a special kind of blood for it. His son, Shinichi Kuruma, and a young girl, Ayaka Sanders, possess that blood, and he will do anything to capture them and take their blood for God's Awakening, and so, humanity will be lost. (myanimelist.net)

Years after the defeat of the Reptilian Empire, Getter Team has begun training on a new super robot, Neo Getter Robo. But a surprise attack from the Empire's revived leader forces them to recruit a street fighter named Go Ichimonji as Getter One's pilot. Faced with an enormously powerful foe, the new team's only hope for victory may lie in the resurrection of the lost weapon of humanity, Shin Getter Robo.