Board Thread:Suggestions forum/@comment-31907131-20170417102331

"The Dwarves were created by Aulë to be strong, resistant to fire and the evils of Morgoth."

-Tolkien Gateway, sourced from Of Aulë and Yavanna (The Silmarillion).

Relatively simple- Dwarves of all kinds should take only half as much damage, or even as little as one damage, from fire and lava. 