Game of Thrones: Who Will Defeat the White Walkers?

While all the noble houses are busy fighting each other, Game of Thrones fans know the real villain is still north of the Wall.

[...] with the White Walker army fast-approaching Westeros, humanity needs to find its savior STAT.

[...] here's an idea: what if all the prophecies about the legendary hero who saves humanity aren't about the same person?