Alien invaders take over Great Mazinger who is at the entrance of a museum next to Mazinger Z as symbols of peace. Grendizer fights the evil invaders and Great Mazinger is recovered.
When the Vegan empire dispatches a new general to oversee the takeover of Earth, he quickly manages to capture Koji Kabuto and, learning of Great Mazinger through interrogation, quickly commandeers it from a museum where it was kept as a symbol of peace.
It is now up to Duke Fleed aboard Grendizer to stop humanity's former defender from becoming its destroyer.
(Source: ANN)
Characters & Voice Actors

Fleed, Duke
Main
Tomiyama, Kei
Japanese
Kabuto, Kouji
Main
Ishimaru, Hiroya
Japanese
Makiba, Hikaru
Main
Kawashima, Chiyoko
Japanese
Tsurugi, Tetsuya
Main
Noda, Keiichi
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