Appearance: Blackstone the Magician #2 (May 1948).
Golden Age Appearances: Blackstone the Magician #2-4 (and a great number of non-Timely issues, see below on more).
Modern Appearances: None.
Dates Active: 1948-?
The comic book and comic strip Blackstone the Magician were essentially Mandrake the Magician lifts, albeit with certain minor differences. I don't remember him ever being given an origin. Like Mandrake, Blackstone had no actual magical powers but fought crime using hypnosis and stage magic. (The stories themselves leave the status of his abilities in doubt, sometimes.) Blackstone is a middle-aged man with white hair and a black mustache who is assisted by the lovely Rhoda.
Note: The Blackstone comics were based on the real life magician Harry Bough, who went by the stage name "Blackstone, World's Master Magician;" for more information on Harry Bough, go here. Bough licensed a series of comic strips and comic books based on his stage image. The fictional Blackstone appeared in a number of comics in the 1940s and 1950s, from Street and Smith's Super-Magician Comics to Charlton's Badge of Justice. For the purposes of my site, however, I'm only counting his Timely publication. His Timely publication occurred through a special deal with Harry Bough himself.
As with Miss Fury, another licensed product Marvel once owned, bringing back Blackstone would undoubtedly pose some small difficulty for Marvel. The rights to Blackstone lapsed after Blackstone #4, and as mentioned he appeared in other companies' magazines after leaving Timely. have in all likelihood lapsed since his appearance in Blackstone. But the rights to the character would most likely be cheap, these days, and Marvel doesn't have anyone like him in their books. The image on this page, by the way, is not a cover image of Blackstone the Magician; I've been unable to find any such thing. (I've been looking for a copy of Blackstone the Magician for going on ten years now and still had no luck.) The image here is from an advertising poster for Blackstone. It's a good image, though, which is why I'm using it.