Possible Clues:

• Underwent the ultimate in horrible experiences here?
• Where the Phlegethon flows
• Pluto's alias
• He'll do for this without an apostrophe
• For this he'll do without an apostrophe
• Underworld leader missing? It's still the underworld!
• (Greek) underworld
• It's hell in this shade
• Pluto tolerated bridge opponents
• Hotness epitome