Board Thread:General Discussion/@comment-25044056-20150503153818/@comment-23932365-20150503172836

While belief is an important role in the afterlife a soul is destined for, what I think plays a major factor is the funerary rites performed. A good example is in The Kane Chronicles, specifically The Throne of Fire: "We couldn't go to Pluto's realm like good Romans," Mad Claude went on, "because our bodies had been prepared for a different afterlife. We couldn't go to the Duat, because we weren't given the proper Egyptian rituals. Our souls were stuck here, attached to these bodies."

Now, since the Abrahamic Heaven and Hell have not been confirmed to exist in the Percy Jackson universe, we can safely assume that the Underworld is the default afterlife for all Western Civilizations, whether the person believes in God or not. The afterlife of Egyptian and Norse mythology is a different matter altogether, because it appears that the only way to enter them is through their culture's respective funerary rites. Hope that cleared things up a bit.