Melchizedek, the priest-king of Salem mentioned in Genesis 14, Psalm 110, and Hebrews 5-7, is a mysterious and attractive figure. "Without father, without mother, without descent, having neither beginning of days, nor end of life; but made like unto the Son of God; abideth a priest continually." This ancient patriarch appears in the Bible from nowhere, receives homage from Abraham, celebrates a sacral meal with him, and then disappears just as mysteriously. One cannot help but wonder if the text is hinting that he has been assumed into heaven bodily, like Enoch, Elijah, and Mary.
Now consider the mysterious figure of Merlin. His origin is a mystery. One rumor held him to be the son of a nun by a/the devil. He doesn't die, but is sealed up in a cave or tree, and there is an expectation that he will return with Arthur in the hour of England's greatest need (don't make me wrestle you to the ground and confess that C. S. Lewis' greatest novel is That Hideous Strength). Now my "What if..."
What if Merlin is Melchizedek?
A figure whose wisdom has been accrued through the ages. Perhaps he is one of the nephilim and that's the source of his non-human origin and the taint of a fall. He could then be a master of angelic powers in addition to the wisdom of the ages. I have figured for years that someone would have made this speculative or imaginative connection, but I have yet to have found that it has been made before. If it has, please point it out to me.