The Hellfurnaces are mostly barren of ice, although the occasional snow-capped peak can be seen. Travelers are never out of sight of some smoke plume, hot spring, or other sign of volcanic activity.
The equatorial Hellfurnaces seem even more violently volcanic than the portions that border the Flanaess, with six major volcanoes and a dozen minor ones identified.
Features and settlements
Some of the most infamous Underdark regions in oerth exist beneath the Hellfurnaces, including the Vault of the Drow, the Sunless Sea, the realm of the Lerara, the White Kingdom, and Dra-Mur-Shou. Aboleths, kuo-toans, svirfneblin, illithids, drow, cloakers, and duergar all war beneath the depths.
The legendary Passage of Slerotin connects the Sea of Dust to the Yeomanry through the Underdark.
On the surface, volcanoes and heat-loving monsters dominate, including fire giants with their hell hound pets, and red dragons with their firenewt servants. Manticores are common in the lower altitudes. Other races found in the Hellfurnaces include bugbears, cave-dwelling humans, firedrakes, fire toads, storm giants, goblins, orcs, ogres, pyrolisks, and trolls. The storm giants have little to do with their fire giant cousins, though they occasionally meet with them.
The Hellfurnaces were known simply as the Southern Crystalmists before the Rain of Colorless Fire, when it is said that the cataclysm ignited many previously dormant volcanoes. Prior to this, an ancient war is said to have been fought between giants and dragons, both sides recruiting orc mercenaries and the Suel Imperium even becoming involved.