Quote Originally Posted by AssertnFailure
Then there's shukaku....who lived on even when the priest he possessed died.
But thats possessed, The nine tails was sealed inside naruto, not to have control over him (though naruto does lose control). I think if the demon is seperated from the person, by force, or was possessing the user instead of sealed in it, then it will live on.

I guess sealing would be like the demon would be a fetus inside a person and is tied to the life of that person much like a baby to its mother.