Breath of Zehir
Lying in the shadow of the adjacent Ruby Peak, Onyx Peak receives little sunlight and appears constantly shrouded in darkness. Volcanic, like its neighbor, Onyx Peak is inactive and its caldera has filled with water.
The Earth Titan Rumdum and his Hill Giants and Ettins conquered the mountain by digging tunnels that drained the caldera, leaving the black dragon Hauntelenash high and dry. Most of these tunnels have long since collapsed and the once-deep lake has become a shallow bog. Rumdum’s Throne now lies submerged under the lake; it is virtually impossible to find if you don’t breathe underwater.
Following the river streaming off the mountain is the clearest way up, the river banks not as thickly forested as the impassable jungle around it. The trees are mostly bereft of leaves; vines and thorny briars are thick upon the trees, choking the life out of them. The normal variety of woodland species is diminished here, with plant monsters, aquatic reptiles, and giant insects accounting for most of the life.