Hehe... yeah that's the awesome thing with mutated creatures - you don't have to bother with creating correct human anatomy, you can just go all crazy and creative
Hm, I wonder what it would look like if you'd replace the handle of that mace with some sort of chain? Of course the rig would need quite a few more joints but it might look a bit more dynamic especially when animated... might be quite a challenge to animate though, especially with making the animations flow into each other seamlessly ^^