One of my favorite serials was THE MYSTERIOUS DR.SATAN from Republic. It featured Eduardo Cianelli as the eponymous Dr.Satan. But what really made this chapter-play special to fan-boys was the introduction of the masked hero known as the Copperhead played by Robert Wilcox. The story has attorney Bob Wayne (Wilcox) thwarting the plans of Dr.Satan, his minions and a robot of the renegade scientist's design. Wayne learns in the 1st chapter that his late father was the masked vigilante of the wild west known as the Copperhead. Wayne decides to take up his father's mantle to run Dr.Satan to Earth.
The story behind the story is that Republic was negotiating with National Periodical Publications to produce a Superman serial. When negotiations fell through Republic tweaked their script and created a new hero. One without "powers and abilities far beyond mortal man". Creating another "superman" might have stirred up a hornet's nest. And so a masked mystery man along the lines of the ones in the pulps was created. Someone like the Green Hornet of radio fame.
Now if you watch THE MYSTERIOUS DR.SATAN knowing about the history and connection between the Lone Ranger and Green Hornet you'd come away saying Republic's screenwriters borrowed freely from the Green Hornet's origin. That is until you realize that the Lone Ranger/Green Hornet connection wouldn't be solidified until 1947. Some 7 years after THE MYSTERIOUS DR.SATAN was released. It was in an episode titled "Too Hot To Handle" broadcast on Nov.11, 1947 that Dan Reid Jr. tells his son Britt that his great uncle was the legendary Lone Ranger after Britt reveals that he is the notorious Green Hornet. Dan Reid Jr. would even appear in 14 episodes of The Lone Ranger television series portrayed by actor Chuck Courtney.
In any case like the Masked Marvel and many other Republic serial heroes there were no follow-up adventures in the movies.* More's the pity. But in the alternate universe that runs through my mind Republic put out their own line of comics. Ones that featured the further adventures of their classic serial heroes. One of these titles was Masked Detective Comics which alternately featured the exploits of the Masked Marvel and the Copperhead. Below is two covers of such a comics imagined by my buddy Vance Capley.
*Editor's notes: The Copperhead returned in a full color semi-remake of the serial in the 1973 Turkish film Yilmayan Seytan (aka The Deathless Devil/Copperhead vs. Dr. Satan)....and an unfinished sequel titled The Return of the Copperhead which you can read about here: http://www.rotc.elfess.com/