MUSPELHEIM

The bottom side of each Ysgardian earthberg is a crimson field of spouting flames. This provides the ceiling to Muspelheim, the realm below the earthbergs, and it shares many traits with the Plane of Fire. Rivers of earth run through an infinite sea of moving, shifting lava, and titanic shards of obsidian rise up regularly to pierce the reddened sky. Fire giants, smolder jotun, and numerous creatures of fire and brimstone occupy Muspelheim, and while it is largely inhospitable it isn’t necessarily evil.

Many jotuns maintain enormous forges in Muspelheim using ore mined from the floating earthbergs or dug up from Nidavellir below. The largest of these is the massive complex called the Brimstone Forge, where jotuns of all kind come to craft mighty weapons and armor.