It's not a Blood Wolf exactly, but this might help a bit to get the 'feel' of them.

They came through the snapping stems in a rush of crimson, their flayed flesh covered in bony knots, horns and hooks. Larger even than a Space Marine in full panoply, muscles burning with Warp-fed energy, eight equidistant eyes marring each split skull -- rolling in madness and fury -- they came. Jaws full of obsidian teeth snapped. Gobbets of fiery mucus slavered from muzzles slick with fresh gore.

The hounds had fed well, and recently, but as there could never be enough blood flowing beneath the Brass Throne, as there could never be enough skulls to fill the war-god’s realm, so too could their hunger for souls never be sated.