Hell is where evil animals go when they die.
After Heaven was created Cleopatra (she is still alive) was refused to train in Heaven so as a punishment she created Hell and the hell training ground. Sometime later the leader of heaven tried to get some powers but he was killed by Cleopatra in heaven showing that you can die again.
Hell Training groundEdit
The Hell Training Ground is where non dead cats go to for Training, Lumina and Triton are two of the Trainees in it, If they get hurt in their dreams they are hurt in the real world. When they learn a move in Hell they get that move in real life.