OK so, Sybill Trelawney's first prophecy makes Harry and Voldemort's relationship very clear.
The one with the power to vanquish the Dark Lord approaches ... born to those who have thrice defied him, born as the seventh month dies ... and the Dark Lord will mark him as his equal, but he will have power the Dark Lord knows not ... and either must die at the hand of the other for neither can live while the other survives ... the one with the power to vanquish the Dark Lord will be born as the seventh month dies ...
Which led this brilliant Imgur user to notice that the prophecy was actually leading to a very different, much darker, ending for the series:
If you need a second, I totally understand.
