What is the forbidden realm?

The Forbidden Realm is a place where you will be sent to if have done very bad deeds and your soul will lost in a river of darkness...

Here's the levels:
Heaven
Overworld <----- You are here
The Web
The End
The Deep Web
A Jacob
The Dark Web
The Nether
Hell
The Forbidden Realm
The Deep Forbidden Realm
The Dark Forbidden Realm