Dean's children are human and so are Sam's: they are born and grow and live and die like any other human, like every other human, like everyone Sam and Dean tried to, would still, die to save. But Dean and Sam stand guard at the gates of Eden, protecting Earth against Heaven and Hell with the power that was once Michael's and Lucifer's, and death is no longer permitted to them. A thousand years in their sight is as yesterday, a hundred years an eyeblink, and they have each other and that will always be enough, but—it never grows easier to watch flames flicker around their own blood and bone.