You describe so beautifully just how the “pagan and Christian dialectic” (as I refer to it) of the Fisher King and the Holy Grail becomes a rather mysterious hybrid of Nature and the Supernatural (even in Christianity) because it is formed from two completely different source materials yet still has such common ground in birth and rebirth.

The Mabinogion has a magic cauldron in place of the Grail.

Glad to get your juices flowing just like the Fisher King?! Or is it the Fisher Queen now?