Supernatural

Ghosts and skeletons are a frequent presence in Hell and are responsible for unique Hell Achievements:

• Skeleton Terrapus
• Ghost
• Revenant
• Dire Revenant

Note that supernatural creatures also spawn occasionally as part of Pandora's Box events.

Standard

Some normal mobs can be spotted in Hell as well:

• Baby Terrapus
• Adult Terrapus
• Flame Terrapus