One of the things I liked the most about the new Dark Knights is the Death Metal Guitar! Cool looking back item (though a bit oversized, imo), but great if you want to have that Heavy Metal Hero (or Villain) look. I've added a couple of guides below to help you get your own axe...
(Multiverse)
(Obsidian Chill)
With that being said, do enjoy and I'll see you rockin' in world!