Stygia

The fifth level of the Nine Hells is proof that hell has, indeed, frozen over. Most of it consists of ice covered by snow. The winds are chilling to the core and often obscure the surroundings. The only truly open water is the river Styx which pulls chunks of ice on its way through the Hells. Many Yugoloths travel here to trade more secretly than they can on Avernus.
For a very long time, the layer was fought over by Levistus and Geryon. Their last battle threatened the stability of the region and Asmodeus declared Levistus the winner and made him Lord of Stygia. But at the same time, the new Lord was punished by being locked into an iceberg somewhere in the layer. Meanwhile, Geryon hasn't given up quite yet and the landscape is scarred by the conflict between them. And there are still skirmishes between the different forces.

Fauna & Flora

The monsters and plants living here are truly exotic and many of them exist nowhere else. Ad behind every icy cliff lies another danger. Any visitor who doesn't know their way around is likely to become a frozen snack for some creature to have for gnawing on when they get hungry. If the visitor is lucky, they won't be alive while stored as refrigerated dinner.