Talos was a Dragonborn. He then became Tiber Septim. He fathered an unknown child. And on his deathbed he proclaimed his grandson, Pelaglus as the new Emperor thus the Septim dynasty was born. In theory; The Last Dragonborn (who I'm going to call Ysmir for ease) sided with the Stormcloaks and freed Skyrim from the Empire. If he actually fathered a child with his [censored] instead of his pen, then Ysmir's child would have Dragonblood. If Ysmir chose, he/she could make a play for the throne of Skyrim. I mean the people would surly support the Dragonborn, the Nordic people would compare him/her to their greatest hero, Talos. Ysmir could mirror what Talos did and maybe even ascend into a God?
This is all wild speculation and I maybe wrong on everything I just said. But it seems to me, who as some understanding of TES Lore, this maybe possible.