Gaiking

Gaiking is a Japanese Super Robot mecha anime series produced by Toei Animation. The first series as aired from  April 1976 through January 1977 through 44 episodes. A 2005 reboot of the series entitled created by Go Nagai was aired on TV Asahi from November 12, 2005 to September 24, 2006 for 39 episodes.

The original 1970 series was done by Akio Sugino, but in reality, was Go Nagai's. Toei deliberately took Nagai out of the credits in order to avoid paying him royalties. Because of that, Nagai sued Toei and refused to collaborate with them for many years. The legal battle lasted over a decade. Nagai himself confirmed that he was the creator of Gaiking at the 2007 Naples Comicon.

Plot
The Planet Zera is on the brink of destruction due to an incoming Black Hole, but Prince Darius led the planet's rebels becoming their savior. Creating the "Dark Horror Army", Darius led them to search for a new world to inhabit eventually coming to Earth. To ensure no obstacle should cross their path, Darius sent agents to eliminate possible threats, especially for baseball star, Sanshiro Tsuwabuki for his latent psychic powers. Thus the Combat Force was founded to pilot the Daikū-Maryū to fend off Darius and his invading army.

Legend of Daikū-Maryū
Five years ago, Daiya Tsuwabuki was on a fishing trip with his father when giant monsters attacked. The boat sank along with Daiya's father and the crew while Daiya was saved by the crew of Daiku Maryu. In the present, Daiya believes that his father is still alive, but no one believes him, not even his own mother. However, when the same monsters attack the city, Daiya becomes the pilot of Gaiking and joins Daiku Maryu as they go to the world of Darius to stop them from taking over the Earth.