Yes! And I'm wondering ... I think the Greeks didn't really have an organized religion in the same sense as Christianity. I mean they didn't have councils debating the tenets and rituals, did they? They really didn't have the concept of heretics, right? I think it was more organic and localized.
I think they do have various temples to 'accepted' gods, but Neptune, for obvious reasons, is the main or maybe even state religion. The darker gods, however, would have to be small and secret. It would be interesting to see how they survived ... if those dark gods actually gave power, that kept their religion alive. Which would be awesome to see them playing a role in government and conflicts with Namor.