What was the first film to use flaming/on fire swords? I'm most interested in when they're used in an offensive manner.
So far most of the film references I've found were to more recent fare (Scott Pilgrim for example) so I'm not sure what film is the first to have fire swords. However, I believe that I can answer your first question, the one about who started this crazy idea. In Genesis 3:24 after driving the humans out, God places a Cherubim with a flaming sword on the path to Tree of Life to guard it.