I don't know the fluff (which you either care about or you don't), but that saw weapon looks like it would do some hell on a sculpture or something. Maybe you could show him defacing the imagery or iconography of his enemy? If you care about the GW fluff, or if he's perhaps for a GW-only competition, you could either adapt some canonical 'biographical' details or develop some bit of fluff that squares with the known history of the character.