The First Dwarves

The First Dwarves are said to have been created by Soldin and Jorthea in an effort to free Brunis from the forge of the world. They were tasked with digging deep into the world.
The first dwarves did indeed dig deep, right down to the very core of the world aeons ago. However when they did so their was a violent eruption as Brunis's fury burst forth into the world, shooting through the mines and scorching a path right through to the surface and beyond into the sky. The eruption was so fierce that is pushed the rock up around it forming the world's tallest mountain.
From then on, the dwarves realised that to release Brunis from the forge would cause a cataclystic event that would destroy all life on Aethea.