I took the default groin for the Wardog and added custom designed Khorne iconography onto flat surfaces. Toyed a bit with where and how big for a bit and noticed that the under carriage of the groin was rather flat and blank as well. I took the World Eater coin from alphaflight83's designs, cut it in half and put it into place. I then copied the groin half I was working on and flipped it around making a mirror image.
Note: I strongly advise supports touching build plate in Cura. Not sure what it'd be called in other software. There are some overhangs I've added that could due well to have the supports. If this is a problem I can look at splitting the iconography off for flat printing.