In TES3:You got the positive sides of the Blight without the negatives, giving you immunity to age.
In TES4:You became a Daedric Prince.
In TES5:Things are a bit more complicated.If you are a Nightingale,Dark Brotherhood Assassin,Azura Worshiper,Werewolf and Nord and you get soul trapped, your soul can go anywhere.But that does not have to be the case.Somehow in TES5, the player will receive immortality(well, you know what kind I refer to), but not as a Vampire.Absorbing an Uber Dragon's Soul.Harnessing insane ammounts of magical energy?Eating an incredibly rare and beneficiary herb/drinking a potion of immortality?
What do you think.How will the Dovahkiin become immortal(if he/she becomes immortal)?