Saw this on both Japanese sites and 4chan today. Allegedly it's a picture stealthily taken of Kamen Rider Gaimu... from the back. This confirms my earlier suspicion that he's samurai based.
Note the person standing on the board in front of the light diffuser on the left wearing the yellow shirt. He is wearing the same belt as the samurai on the right. This means that most likely, they are filming a transformation scene, and the Rider actor is about to step in to replace him. The platform he is standing on is typically used as placemarkers so the hero doesn't step too far out of the shot. I have to admit, I do rather like the bronze, gold, and blue color scheme.