Emperor Zeba's Possible Character Planning and Eventual Development
Well I've mentioned how I was surprised to find this earlier promotional shot of Zeba in Maskman so it seemed he was planned to be a human being or not. However I thought that it was entirely scrapped in favor of the nightmare fuel behind his true identity. So I guess the human face Zeba was scrapped off in favor of the more badass Zeba with the face mask that conceals his inhuman features except his eyes.
Instead, they decided to remove the whole Zeba with a face to Zeba being your suspicious tyrant yet you don't dare question him why you never see his face because he'll torture you horribly before you can spill the truth out. For starters, it's obvious he isn't your normal human being though you're probably kept wild mass guessing to what he is (I even speculated he was an alien from outer space or some demon) until you see more hints that lead towards his true identity. Most of the plot pointed out to the possibility he could be the legendary monster Lethal Dobler. True to his name, he not only usurped the kingdom but also, ruled it with a real iron fist. Most of the hints seem to suggest he was really Lethal Dobler though it was later found out he had died. If Lethal Dobler had died, who was he then? Every time somebody got close to his identity, we are treated to the mystery being unwrapped yet leaving us with some more plot details that won't unwrap until we reach the finale arc.
That of course, the speculations of what Zeba is was really slowly put aside with some good writing. That is in episode 50, we realize that even when Lethal Dobler died, we see that the dying monster by some supernatural methods conceived Zeba as his son. Zeba is in short, the second Lethal Dobler.