Religion

Still more work to be done here...

Just because these people constantly interact with the spirit realm does not mean that they are any more certain of an afterlife that the rest of the world. They deal strictly with the middle ground between this world and the next. Whether there is a Heaven or Hell, what those places are like, and how someone is chosen to get into either is entirely up to personal beliefs. There may even be Hunters who are atheists and believe that once a spirit leaves this plane that there's nothing afterward, but they do what they do because a spirit can't stay here.