Board Thread:Lore Discussion/@comment-2.100.92.38-20130821124429/@comment-24434525-20140130204250

Could be a shezarrine but by the description so could Ulfric Stormcloack. Nothing in Skyrim ever suggests that the Dragonborn is shezarrine, again that is left up to the player and is completly open to interpretation. The ghost is a simple side quest, one that can be ignored and has no bearing on the actual story, therefore it is optional.

I think you are reading way too deep into it. Now if you want to use that angle for your character, great, your Dragnborn is the return of Tiber, wonderful I hope you have fun. But that doesn't mean everyones dragonborn is the reincarnation of Tiber Septim. The entire point of the TES series, (and most every RPG style game Bethesda makes), was the freedom to play how you wish to be the character that you want to be, not the player that was designed for you.