UFO Robot Grendizer vs. Great Mazinger

UFO Robot Grendizer vs. Great Mazinger is a short animated film featuring characters Grendizer and Great Mazinger and is inspired by a few chapters of the original Grendizer manga. Like other Vs. movies, it is non-canon to either series.

Plot
After numerous failures against the Grendizer, King Vega sends General Barendos and his troops on a mission to Earth. Before landing, Barandos takes the opportunity to gloat at Blaki and Gandal that if he succeeds in his mission, they will prove too useless and killed.

Using the Saucer Beast Jinjin, Barendos captures Koji Kabuto in the TFO. Koji is then brainwashed to reveal the locations of the Mazinger Z and Great Mazinger. Taking the latter mecha, Barendos pilots Great Mazinger in order to battle against Grendizer.

The giant robots clash for a while until Koji tells Duke Fleed about a place to deactivate Great. Duke complies using a special shot, which allowed Koji to use Great after Barendos escaped it. Grendizer then proceeds to destroy the mothership Barendos is in. With the threat stopped, peace had returned and Great Mazinger put back in storage.

Production Background
Grendizer vs. Great Mazinger uses materials from a couple chapters in Go Nagai's Grendizer manga. The use of brainwashing was used by a soldier of the Vegan Empire to take control of both Koji and Tetsuya Tsurugi for them to pilot Z and Great. Barandos himself appeared in a chapter, taking Great Mazinger and a few Mechanical Beasts in a battle against the Grendizer.

Trivia

 * In the movie's flashback, Mazinger Z physically resembles a hybrid between it and Great Mazinger and is depicted killing Dr Hell with a Great Boomerang esque attack while Koji is hallucinating. Considering Koji was under Vegan hypnosis during this flashback, it's possible his mind was merging his time with Mazinger and working alongside Tetsuya rather than depicting an actual Mazinger design.
 * This movie was one of several Vs. films included in the French Compilation film Le Retour De Goldorak and the events of the movie are the subject for the movie's theme song "Goldorak Et Mazinger". It is also featured in the Italian compilation film "Mazinga Contro Gli UFO Robot" and is the star billed event in the compilation.