User blog comment:Fusedtwilight/The New Death/@comment-95.112.197.243-20160220140618/@comment-95.112.197.243-20160220143856

Right, only Death himself claimed that God can die. If it turns out that Amara can't be destroyed, it's reasonable to think God as her younger brother can't be destroyed either.

The books differed in small things, but the overall results were God's will.

Who said Lucifer had free will prior to season 6 ? Lucifer himself said that "God wanted the devil". God wanted Lucifer to bind Death, God has written it in the SPN books.

Death might also be younger than the archangels, at least Amara didn't know who he was. Maybe he just had another name back then and was later called Death, maybe Amara lied (but why ?) or more likely, Death came into beings after the Darkness was sealed away.