I recommend for Morde Rework
Instead of getting rid of the "metal" concept because you don't know how to build around it... You get creative and START with Metal Mage and go from there.
I'll provide some inspiration:
This is Sauron. Consider him the iconic character trope you're trying to build up with Morde. https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTh7rcP9GSMATMSvVfIrsANfQqz7Bg47mVCaDhPIrhMs-YUCdzYXymzzO4
Pretty awesome right? He blasts spells, and swings his mace. He's a pretty epic dude.
Consider that Morde isn't some ghosty ethereal shadow isles master like the others. He's the recruitment department. He's not just here to rule the undead, he's here to get some living, and turn them to their cause.
Here's some music for inspiration
https://www.youtube.com/watch?v=N3CQfvfv1sI&list=PLB529A97DF1A7694E&index=29
https://www.youtube.com/watch?v=Q1bif8TsDRM&list=PLB529A97DF1A7694E&index=15
https://www.youtube.com/watch?v=lOKbMW2uqs8&index=13&list=PLB529A97DF1A7694E
https://www.youtube.com/watch?v=mSLqhZk-hA4&list=PLB529A97DF1A7694E&index=10
