Possible Clues:

• It's hell before public vehicle comes along
• Darkness personified, in Greek mythology
• Antarctica's Mt. ___
• Darkness descends with last bit of the puzzle
• Volcano's showing changes, to be sure
• Active volcano on Antarctica
• In place of darkness finding east a puzzle
• God of darkness — cavern on the way to Hades — active volcano in Antarctica
• Antarctic volcano; region between earth and Hades
• Be sure (anag) — Greek god