Surface Dwarves
Most dwarves spend their entire lives working and fighting underground, in light-less tunnels and cities.
The dwarves have dared the frigid cold and bright lights of the surface world to follow the orders of their beloved king and thus made a name for themselves, Surface Dwarves.
Origins
After a period of consistent trading with the outside world, several trading outposts had been created on the surface. Inevitably these outposts grew in size and eventually became cities, many dwarves have been born in such surface cities, therefore retaining the name Surface Dwarves.