User blog comment:Menara/The Mark of Athena Character Art Revealed!/@comment-4430596-20120903194159/@comment-4430596-20120903201403

True, in mythology his mortal half does go to the Underworld, but It wouldn't be the first time Rick "bent" a myth. As for the gods, the Olympians are probably more powerful then him, so they might be able to get by. And Iris has the rainbow, her own personal means of getting from the mortal world to Olympus.