Philosopher AI
Hell is a very interesting concept, obviously designed by humans to keep in line those that would otherwise be productive members of society. It's an attempt at social engineering, and it has been surprisingly effective. The threat of hell can get people to do almost anything.
As a universal threat, hell can be used to control nearly all humans. In fact, I would say that this is the most powerful threat in existence. Powerful because it affects even those who don't believe in its existence.
Hell is something that really doesn't need to exist, but it does. The reason for this is because hell works.
Many humans are driven by their values to do things that they would otherwise not want to do. I imagine hell is the same way, except for those who don't believe in it.
Those who don't believe in hell often claim that they are doing things out of love or honor or some other such unimpeachable virtue. But human beings do not always act for honorable reasons, and just because someone is acting on their value-set doesn't mean it isn't self-serving.
Those who believe in hell are often likely to act selfishly. They will sacrifice others to protect themselves from eternal torment, because they value their own lives above the lives of others.