We all know the plot of Skyrim.

You are the Dragonborn. You must defeat Alduin etc. etc.

But there are a lot of questions to be asked.

Why was the Dragonborn trying to cross the border, before he/she was captured and sent to Helgen?

Does the Dragonborn have family?

What happens after the events of Skyrim, Dawnguard and Dragonborn?

Well, looking through the game, I think we can answer all those and more.

WARNING: This is all speculation and may or may not be true

Firstly, the Dragonborn’s backstory. During the quest “No One Escapes Cidhna Mine” the Dragonborn mentions he/she has family, and that he/she possibly killed one of their relatives. When talking with Serana, dialogue will come up asking the Dragonborn about his/her family. Here the Dragonborn can hint about their relationship with their parents, and their possible fate. One of which, the Dragonborn’s parents are no longer alive. Furthermore, during the quest “The Taste of Death”, the Dovahkiin can say whether they killed a sibling. All this leads me to believe that prior the events of Skyrim, the protagonist killed their family (for whatever reason), and they tried to run to/from Skyrim because of this, before being captured at the border by an Imperial ambush. We have other clues about the Dragonborn’s past. Regardless of which race you choose, you start off with flame and healing spells. This suggest that before the Dragonborn was captured, they were learning magic.

But what happens after Skyrim? During the events of the Dragonborn DLC, the daedric prince Hermaeus Mora hints at the Dragonborn’s possible fate, with the following. "If you tire of your search, read your book again to return to your mortal life. For a time. The lure of Apocrypha will call you back. It is your fate." This suggests that after the events of Skyrim, Dawnguard and Dragonborn, the Dovahkiin might stay in Apocrypha. This is further strengthened by the fact that Hermaeus Mora making the Dragonborn his champion after defeating Miraak.

After that, the Last Dragonborn’s fate is a complete mystery. If the Dragonborn becomes a vampire (as is possible), then he/she may live forever, assuming they aren’t killed. If the Dragonborn decides to become a werewolf during the Companions Questline and doesn’t cure his/her lycanthropy, after their death they may reside in the Eternal Hunting Grounds of Hircine. If the Dragonborn does the Thieves’ Guild Questline and becomes a Nightingale, then they may have to serve Nocturnal after death until their contract is complete. If the Dragonborn does the Dark Brotherhood Questline or is killed by the Dark Brotherhood, their soul may go the Void with Sithis. However, if the Dragonborn does none of these, their Soul may very well go to Sovngarde. The Dragonborn is obviously worthy enough, and they have been to Sovngarde before, albeit still alive while there.

Tell me your thoughts on this topic, I’d love to hear them.

The Dragonborn, like the Hero of Kvatch and the Nerevarine, is an enigma. Deliberately so. Their past, their family, their origins and experiences, are up to YOU to decide. History will not remember them, it won't even know them, which is the most liberating element of the characters. They can be anyone, from anywhere. They have no history until you write it, and only you will ever remember it. All Tamriel will know is what they did.