How do the Anvil of Doom work in battle?

[Erikjust]

I often wondered how the Anvil of Doom works or put in another way if you were standing next to the Anvil of doom during a fight how would it look when firing of its runes?

Would it be that the runesmith hammers the rune into shape and then as the last hammer blow falls the rune releases its energy either through the anvil and into the ground and then proceeds to fly of and hit the enemy or is it more like it fires of a lightning blast that hits the enemy or how?

And also the anvil itself does it just look like a normal anvil or can one see the magic swirling around it?

So is there any official fluff that answers these questions?

[Munin]

An Anvil of Doom is used by the Dwarfs when fighting the Elves in the novel Oathbraker. There its somewhat describe how it looks and works. Unfortunately I dont remember exactly what it says.