Radîn-Zukthol is a volatile wasteland sited in eastern Onvorn. It is an active volcanic area that borders the Great Tradeway. Radîn-Zukthol was created when Armorn was sealed by the Ankh of Phalgas. In the Second Epoch, heroes of the Golden Elite used this Ankh to cleanse the Sylvan Kingdoms and bring an end to the devastation caused by the two artifact created volcanoes of Ginzarak. When the volcanoes were sealed, some of the lava diverted from Gûn could no longer feed into Armorn, so it spilled into this vast Underdark area.
Radîn-Zukthol is the abode of salamanders and other fiery creatures left over from the time when Katrana ruled the lands above. These creatures often raid Maharâg and sometimes climb the old lava tubes and chimneys rising up to the surface. Once at the surface they raid the lands around and carry out pyromaniac deeds.
This wasteland of the Underdark is covered in andesite, lava stone, and a source of fire opals. Some of the largest of these gemstones have been procured from this area.