Ever since Persona 2 the main characters' starting personae have all been from a single ancient mythos. In P2 it was Greek/Roman (Apollo, Maia, Artemis, etc.), P3 was Greek again (Orpheus, Hermes, etc.), and P4 was ancient Japanese folklore (Izanagi, Amaterasu, etc.).
What ancient mythology do you think the P5 protagonists' personae will be from?
There seems to be a "journey to the underworld" pattern with the MC's persona. Both Orpheus and Izanagi went to the underworld to try and rescue their wives.