Netherworld

The Netherworld is a location mentioned in Paper Mario: The Thousand-Year Door.

History
The Netherworld is mentioned a few times in the game. Once by Craw-Daddy of the Glitz Pit saying he will send Mario to the depths of the Netherworld after his defeat. The other time is when the Shadow Queen is mentioned to be banished to the Netherworld after her defeat.