Spectreman is about this sentient android, who disguises himself as a man called Jouji, that is sent to Earth to stop the mad simian runaway-convict, Dr. Gori. Gori came to Earth wanting to claim it for his own because he was taken in by it's beauty, but then he sees that man is polluting the Earth, and decides to destroy humanity by using the very pollution they've caused to make monsters. But when Gori unleashes his monster of the week, Jouji raises his right arm and becomes, Spectreman the golden masked defender of the galaxy, to combat Gori's mad creations!
Gori was the original star of the show, the show was actually named after him, then after a third in to the shows run Spectreman's name was added, then 2/3rd's later Spectreman stole the show completely. The show was made by P. Productions in the early 70's, they are the same company who made Ambassador Magma in 1966, which was Ultraman's rival show.
So feel free to take a look at Spectreman wiki, and see if it's something you might be interested in.