We're talking about a religion here that existed, in a form that we understand, with actual myths attached, since the 7th-8th century BCE, and continued to be in wide practice(relatively speaking, near the end) until the 3rd or 4th century CE, where its myths have been added to, altered, and so forth in that gap, with the names of gods changing, and new gods being spoken of, that were never even mentioned or thought of, in earlier versions, due to not being conceptualized yet. Hellenism, or Greek religion, is also seeing a resurgence of sorts, in modern times, so it's likely that if it gets bigger(it prob will, as it got big enough already that Greece has recognized it once more as a proper religion for practice), there'll be new myths added on, as well as new retellings of old myths. That's just how it goes. And even then, when that happens, that'll just make them the most recent versions from its followers, as even they will tell you, if asked, there is no, and never will be, a...