This is from the Mistborn Prologue Part One Annotation:
Somewhere in the italicized pre-chapter blurb of the prologue here is the clue one needs to figure out the over-arching mystery of the entire series. If you figure it out, good for you! If you don't, you'll have to wait until the last chapter of the final book to get it explained. . . .
Here is the logbook entry:
Sometimes, I worry that I'm not the hero everyone thinks I am.
The philosophers assure me that this is the time, that the signs have been met. But I still wonder if they have the wrong man. So many people depend on me. They say I will hold the future of the entire world on my arms.
What would they think if they new their champion-the Hero of Ages, their savior-doubted himself? Perhaps they wouldn't be shocked at all. In a way, this is what worries me most. Maybe, in their hearts, they wonder-just as I do.
When they see me, do they see a liar?
What, if any, connection is there between the "over-arching mystery of the entire series", who/what the Hero of Ages is, and this specific logbook entry?
According to the logbook we know Alendi heard the 'thumpings' and saw the Mist Spirit. These were things none of his traveling companions were aware of. It is assumed that Alendi was the Hero of Ages, even though he didn't do anything at the Well and it was Rashek who took the power. Alendi was quoted from the logbook as saying "If there are prophecies, if there is a Hero of Ages, then my mind whispers that there must be something directing my path. Something is watching; something cares. These peaceful whispers tell me a truth I very much want to believe.
If I fail, another shall come to finish my work." Vin is aware of the same things as Alendi was. Would it not make sense for Vin to be the Hero of Ages reincarnate?