Mouth of the Daemon

The only passage to Daemon's Crag is through the Mouth of the Daemon&mdash;a cavern through which a river of boiling lava flows, created by Pyros. There is no secure path that anyone on foot can take through here, so reaching the crag thereafter requires some resourcefulness.

In Ultima VIII, the Avatar was able to traverse the river by first, filling Carthax Lake, thereby cooling the lava, and then using the Air Walk spell in a particularly treacherous part of the cavern, enabling him to reach the Sorcerers' Enclave.

Trivia
A bug can be triggered when first entering the Mouth, cutting off some dialogue.