A classic, and patriotic, cover for Superman 14 (Jan/Feb 42).
Siegel, Nowak and Sikela have Superman meet a mermaid in the third story in this issue. It begins as an angry Perry White sends Lois and Clark to check out a man who claims to have seen the sea creature, after the two reporters spend too long at lunch, and miss the mayor’s surprise resignation.
Although Perry does not think there is anything to the story, Superman finds that the mermaid really does exist. She has come to warn people about a forthcoming attack from her underwater city.
The mermaid, Princess Kuella, gets brought back to her city by the evil ruler, Akthar. Superman follows, and gets into a strange digressive plot thread in which he has to pass a series of tests – in other words, demonstrations of his powers.
Finally, Akthar leads his people in the attack, which floods Metropolis. Superman helps to destroy their advanced machinery.
This sets off a chain reaction which winds up destroying the city itself. Kuella chooses to go back and die with the rest of her people.
The Lightning Master faces Superman in the final story in the issue, by Siegel and Nowak. A mad scientist with a lightning bolt machine, the story treats him as if this is his first appearance, but I think otherwise.
Lois Lane meets and unmasks him. Is that not Luthor? The story says no, but why even have him unmasked if he is not someone we have seen before?
Lightning Master continues to conceal his identity when he faces Superman, something not necessary if this is no one Superman would recognize. His lightning bolt weaponry is well within the kind of tech that Luthor has been using in his stories so far.
The story ends with the Lightning Master electrocuted by his own machines. But no matter how you slice it, this guy is not dead. Official continuity has him return in an All-Star Squadron annual. But if you look at Action 42, the next appearance of Luthor, he has gained electrical powers, and goes through the story wearing green robes, much the same as the ones Lightning Master is wearing in this tale.
My theory is that this was written and drawn as another Luthor story, much like the one in the previous issue, where he called himself the Light. Then an editorial decision came down to change it, and make this a separate character, for whatever reason (too similar to the previous issue would be my guess), and so a few panels were re-dialogued, and Lightning Master became a character unto himself.
It’s really Luthor’s robes and electrical powers in Action 42 that make me think this.