I have ammended the rules a bit (here). For simplicity sake I will try and give the existing rules here incase anyone wants to have a go at updating him.
2 separate battles required, the Black Dwarf in one and the anvil in another (so you can see why I’ve changed the rules).
In one battle the Anvil is conveniently near to an open pit of lava (about 2"), and the dwarf player has to get someone inside the mountain to lift it up and drop it in.
Black Dwarf is a sorcerer lord (and army general) with:
Chaos Tomb Blade
Wand of Jet
He cannot be killed (only when the anvil is destroyed).
He costs 493 pts.
There are a load of other rules specific to the scenario, it’s quite a complicated one to explain.