Could it be Mr Mind?

A fair guess, but no.

Captain Nazi ???

OK, it's not anybody from Fawcett Comics.

So, it's not Marvel Bunny then. Good to know.

Was it the Turtle?

Is it The Mist?



...

Good try, since there were so many features in Adventure Comics. But no. The Mist actually wasn't even Starman's most frequent 1940s nemesis; he only fought Starman twice in the 40s. That's tied with The Sun and his Satellites, and in second place behind The Light.

The Gambler?

This is a good question, Custom.

--wyld

You took a chance on the Gambler, but no, not him.

Here's a tip: try to think of three reasonably-well-known heroes who first appeared in the same (1940s) issue, and work from there.

I met up with that guy. It was on a warm summer's evening on a train bound for nowhere.

The original Dr Light.

If I could give negative rep for referencing Kenny Rogers, I would.

That's exactly what I've been doing!

My problem isn't thinking of the heroes, it's thinking of the villains.

Well, the villain in question did make an appearance in comics published in the 1980s; but other enemies of this hero, who appeared less frequently in the 40s, have appeared more often in the last two decades.

well, i will think out loud, since I am not coming up with anything.

I keep thinking the "more recently seen" villains are probably Flash or Hawkman villains, and they fit the bill. But I can't think of any more obscure villains for those heroes, as I am not that up on my golden-age foes.

What was the name of the guy who killed Prince Khufu? Him?