I already modeled this guy. I took the metal vampire on foot model with sword and dragon helmet for starters (Blood Dragon on foot).
1) remove both arms and used a round ball dremel cutter to remove his head
2) used our empire general kit great weapon arms pinned into the body (it's an almost perfect fit; minor filing makes it perfect)
3) removed that big hammer head and replaced it with a double bladed axe head
4) his new head is an old nurgle chaos lord head that has chain mail mask and hood (horn removed)
5) I added a small amount of green stuff for edge of executioner hood
I use him as a captain in Armor of Meteoric Iron with great weapon and Dawnstone.
My question to you is, could he be a viable special character?.....especially if given heroic killing blow