First Appearance: Daring Mystery Comics #7 (April 1941).
Golden Age Appearances: Daring Mystery Comics #7, Mystic Comics #6-10.
Modern Appearances: Marvel Premiere #29 (referred to)
Years Active: 1941-?
Bill Waring is a meek and harmless law student who is a victim of bullies. He never does much about this, but when his father is killed for giving evidence to the D.A. about an alliance between the Mob and a prominent local politician, Bill swears vengeance. He travels around the world, learning the proper skills to avenge his father and kill criminals. (Capturing the bad guys is not a high priority for the Challenger, who is very much in the Killer Vigilante mode.) The Challenger learns jiu-jitsu in Japan. He learns chemistry in Tibet (Tibet???). He learns nerve control in India, so that he is immune to pain. He learns swordsmanship in Paris and marksmanship in Germany. He learns how to fly in England. He learns how to box. He learns every imaginable skill which might help him in the war against crime. And then he returns to America and avenges his father, after which he takes on various other criminals.
In addition to his various skills, the Challenger is considerably more experienced in the fantastic and uncanny than other, similar characters. A text piece mentioned that he he spent several months in Central Africa and Abyssinia, where he encountered a lost colony of Latin-speaking Romans.
Note: Despite the obvious debt that the character owes to The Batman, and despite the hideously lame costume he's saddled with--I mean, what is that thing over his nose?--I feel that the Challenger has a lot of potential, and I'm quite pleased that he was mentioned in Marvel Premiere #29 and so exists in current Marvel continuity.