What if Sauron's mind is placed inside the body of Eddard Stark shortly before Jon Arryn's death. He has all of Ned's memory but does not have any of Sauron's magical powers so he cannot make rings and will die like a normal human but he has the sliver of the Stark's latent warg powers.
How would this change the story?
Jon Arryn would still die so Robert will likely ask Ned to become his hand again and he would probably accept since that means he has the ear of a king. Alternatively he might decide to stay put and build up his powerbase in Winterfell if he discover's his children's powers . I'm not sure how well he would be as a father though which might tip Catelyn off.
How would this change the story?
Jon Arryn would still die so Robert will likely ask Ned to become his hand again and he would probably accept since that means he has the ear of a king. Alternatively he might decide to stay put and build up his powerbase in Winterfell if he discover's his children's powers . I'm not sure how well he would be as a father though which might tip Catelyn off.