My only concern is that a) you'd basically have to either use some sort of generic silhouette or body shape for the attacks, (picture something like phantom army), and/or you'd need at least 3 versions of the power, (male, female, huge). I suppose you could do something like what shield charge or lightning rod do, but would you be vulnerable/targetable while you're moving around? Also, and sorry for being pedantic, but I always thought that "vorpal" was used to denote something that was unusually sharp, (like the vorpal blade from the jabberwock), or the "vorpal bunny" from Monty Python, not some kind of hyperspeed "flash step"...