Board Thread:Speculation House/@comment-27986488-20160331210606/@comment-24757748-20160402015931

If his Semblance is reflection, then it might have the potential to be the most stupidly overpowered thing in existence. Although it would probably have a few restrictions, such as just how much force it can reflect and how long he can keep it active.

However, it should be noted that the commentary never said it was reflection, but that the white flash in that scene with Cardin was his Semblance. As far as we know, it's simply an impenetrable force field or some sort of repulsion effect (think "Force Repulse" from Star Wars: TFU, gif here ).

Whatever it is, it seems to be reactionary, although that could probably change if Jaune learns to control it better.