The Stainless Steel Rat Goes to Hell, by Harry Harrison, ISBN 0312860633
This adventure that has slippery Jim diGriz gallivanting across multiple universes does not have the quality of dialog that most of the other Stainless Steel Rat stories have. Some of that is made up by the satire of religions, specifically those that offer salvation if you donate a great deal of money.
In this story there is one chief antagonist called Slakey and he is capable of duplicating himself and any other person. One of the most powerful features of the duplication is that all versions of a person are at all times aware of what is happening to the other versions. This allows Slakey to literally be in more than one place at a time and to duplicate another and hold one captive so the other is forced to do his bidding.
Heaven and hell both exist and are simply different universes where entropy operates at slightly different rates. Slakey has developed a way to send people to the other universes and their bodies will adapt to their new surroundings, which can mean a change in appearance. Including their morphing into an actual red devil with a tail.
Given the various environments the Rat finds himself in and the different versions of Slakey that he encounters, there is also less sequential continuity in this story than in most of the other Rat tales. Therefore, I rank this book as a three out of five star item.