User blog comment:Jack Pistol/Immortal Dovahkiin?/@comment-3534737-20121003015124/@comment-2040576-20121003150151

Although that would be epic... The only way I can think of that working is for a former Dragonborn to be resurrected (using the method Alduin uses on other dragons) and then you do battle with him. It would be impossible for another Dragonborn to appear, since you are supposedly the last...

This could actually be a really cool DLC! I am currently thinking of all the possible awesome ideas that could go with it... Perhaps the Dragonborn is faced with some issue, and they are not powerful enough to defeat it. The only way to overcome this issue is by strengthening the player's power with another Dragonborn soul... but there are none left in the world. You find out that, like dragons, Dragonborns can be resurrected so long as their remains are still intact, so you begin a quest to find and resurrect this Dragonborn (perhaps with an epic new shout?) and then defeat him, absorbing his soul. Once you do, it could somehow make you stronger, or maybe you could choose a certain amount of shouts that become a bit more effective. Then it is off to go and deal with the issue that started all this!

It could actually be an epic extension to the Blades, and perhaps the whole quest revolved around them, and the reason you need more power has something to do with them. Perhaps just to increase the power of your shouts or Dragonborn essence? Maybe it is a Blades secret?