(Detective v1 031-032, 1939) The only reason this guy’s minor is that Batman shoots him dead in 1939. I know he’s made a few reappearances over the years but mostly they’re retellings of that first story. Also I guess they’re calling him the Mad Monk now? Weird. My point is that Batman deserves a vampire nemesis so they should BRING HIM BACK. ADDENDUM: it’s very strange to me that in Batman: Red Rain it’s Dracula who vampires Batman and not…
(Detective v1 030, 1939) I like the Master because he is simultaneously brilliant enough to invent a mind control device capable of enslaving a significant portion of the US Government and dumb enough to brag about his machine to a federal agent not ten feet away from it. Machine smashing ensues.
(Adventure 044, 1939) Another early Sandman villain. A fairly standard master of disguise who was later reworked into an axe-wielding maniac in Sandman Mystery Theatre.
(Adventure 041, 1939) A fanatic radio preacher of no specific religion, Mobrune bolsters his reputation by predicting disasters that he then causes. SPECIFICALLY, Mobrune seeds snow clouds with nerve toxin, completely wiping two small cities off the map. A bad dude!
(Adventure 040, 1939) Standard masked crook, remarkable only for being the Sandman’s first foe. Shows up later in one or two crowd scenes. This story is also notable for being the only time Golden Age Wesley Dodds tucks in a little doll version of himself before heading out as Sandman, a charming bit that was later adopted as an ongoing thing in Sandman Mystery Theatre.