It works for everyone except Dragon Knight. His animations are geared towards using a blade, not a hammer or cudgel, so it'll look wonky if he's trying to slice people with the side with the skull decal. You might be ok just leaving it for Slard, Void, and Omni. It could also work for Centaur and Magnus, but it'd need to be a little bigger.

I think this should be the ultra-rare of the treasure with like really cool effects´n shit :^)