Anime Profile: Grandizer

The crown prince of the planet Fleed is forced to flee from his home planet (which bears his name), after it is conquered and destroyed by the evil emperor Vega, to conquer the entire galaxy. Duke Fleed (or Orion Quest in the dub), the prince, manages to escape thanks to the most advanced weapon on the planet, the spaceship / robot Grendizer. After a grueling journey he arrives on planet Earth, where he finds conditions of life similar to those of Fleed. Here the young alien is saved and "adopted" by Professor Genzo Umon (Valconian), a brilliant scientist at the head of a research institute. Umon, to disguise the extraterrestrial origins of Duke, gives him the name of Daisuke (Johnny Bryant in the dub) and presents him to other scientists as the son returned from a long trip abroad.

However, the Vega Empire has not satiated its hunger for conquest and, seeing that their native star is about to die, they decide to conquer the Earth. Thus begins an exhausting war between the aliens and the terrestrials, which are defended by Duke aboard the Grendizer, the extreme defender of the freedom of the planet, which now calls home. Alongside the hero fight the brave Koji Kabuto (Lance Hyatt in the dub), the former pilot of Mazinger Z, the beautiful Hikaru Makiba (Brenda Morgan in the dub) and the young Maria, sister of Duke who was believed to be dead.

In the final episode, Duke Fleed and his friends finally manage to win the final victory over the Vega Empire, freeing not only our planet but the entire galaxy from the evil oppressors. Even the native planet Fleed finally seems to have returned slowly to life, after the devastating attack by Vega that had contaminated it with the evil radiations of Vegatron. Duke Fleed and Maria, aboard the Grendizer, set off again to that world from which they had fled with the aim of making him reborn, bringing his life back to life.

The show was broadcast in English heavily edited as part of the Force Five. Many scenes of violence and sexuality were cut, as well as all mentions of Koji being the pilot of Mazinger Z, as it was either too confusing for kids who haven't seen Mazinger Z, or to avoid legal issues with 3B Productions, which had the rights to the series under the name Tranzor Z. The show was also broadcast in France and Italy under the names Goldorak and Atlas UFO Robo Goldrake, were it was hugely successful, and mostly unedited. The show was also successful in the Middle East.

Summary from encirobot.com