Nothing on the "character" has been revealed, the only known information that coincides with the name is the tomb/vault. In past games were played as characters based off of Ogier and Roland, who's to say we aren't Charlemagne? Still, it seem like they are taking it in a different direction. Maybe he was the first Guardian or something along those lines. Then again, the Traveler was technically (and as far as we know) the first "Guardian" when it protected us. We don't know if the Guardians existed before the Fall but I think it is safe to say we didn't.
Since this thread was bumped, I realised I never responded to you.
I fully agree, that does seem to be what we are. We are the scavengers and the warriors for the Last City. We are the ones trying to defend broken walls and bring back dead gods...and Warminds. A whole lot has been theorised since this thread. If you want to have a discussion about it ever, feel free to message me.