Frost giants are giants inhabiting the far northern mountains of Nordheim. They are the sons of Ymir and the brothers of Atali. Despite their size and strength and divine parentage, frost giants may be slain with mortal weapons. Conan killed a pair of them during his pursuit of Atali.

« He did not wonder at the strangeness of it all, not even when two gigantic figures rose up to bar his way. The scales of their mail were white with hoar-frost; their helmets and their axes were covered with ice. Snow sprinkled their locks; in their beards were spikes of icicles; their eyes were cold as the lights that streamed above them. »

Robert E. Howard – The Frost Giant's Daughter 

Map of the Hyborian age :