What about prophesies that anyone can fill, I mean not that literally
anyone can fill it but it's a description, encrypted or not, such as Mercedes Lackey and Andre Norton's Halfblood chronicals. That holds the whole question about whether or not the charcter is the prophesized one. But then most readers will assume so. There a few twists you can play up, however.
1. there are three candidates that can fill the prophesy and the reader doesn't know which one.
2. the author leads on the reader with one when its really the other
3. someone, how doesn't match the prophesy ends up fulfilling it so that the reader goes, 'wait what? the prophesy said...'
4. The prophesy is fulfilled by the one who is supposed to but in a way that the reader doesn't realize it
5. the reader doesn't know what the prophesy is, just that the MC will do something important to the salvation of the world. and lastly
6. the MC is
not the prophesized one but there's a prophesy anyways. This last one can go several ways, for example,
A.the MC could do something to affect the prophesy or prophesized one, or even be the parent of the prophesized one (a friend of mine did that).
B.Or the MC could have absolutely nothing to do with the prophesy but everyone thinks he does, including himself maybe (kinda like narselon said) C.or even the MC is not the prophesized one and the prophesy is just in there to confuse the hell out of everyone (
)