One can only defeat so many villains that want to "cover the world in darkness" before one starts to look for a different flavor of horrible.
EVIL JUST GOT EMO!
The dwarven gods true names can only be known by dwarves. They are referred to by nicknames in the presence of non-dwarves. I.E. Gudurran( Allfather) Baenna ( Hearthmother) Dudrak ( Ore), etc. No torture or magic or direct intent can reveal their true names to non-dwrves.