Mouth of the Daemon

The Mouth of the Daemon is a cavernous stretch of lava-filled tunnel appearing in Ultima VIII.

Description
The Mouth of the Daemon provides the only means of access to the Sorcerer's Enclave in Daemon's Crag, home of the acolytes of Pyros, the Titan of Fire. It is almost entirely occupied by a river of boiling lava, created by Pyros in order to isolate the Sorcerer's Enclave from disturbance. Ordinarily impassable, while stranded on Pagan the Avatar was able to traverse this river by first filling Carthax Lake—thereby cooling the lava with the overflow—and then using the Air Walk spell in a particularly treacherous part of the cavern, enabling Daemon's Crag to be reached. In doing so the hero encountered the sorcerer Beren, who proved displeased with the turn of events enabling passage through the Mouth of the Daemon.

Trivia

 * A bug can be triggered when first entering the Mouth, truncating dialogue from Beren in which he elucidates the reason behind his sour disposition.