With all this talk of "Elune forsaken us" and all of the Night Elves going to the Maw after the destruction of Teldrassil... What if the Jailer and Elune are THE parents of the whole universe, and the parents of the titans? Still within the theory that the Jailer was banished into the Shadowlands by the pantheon / his children. And with Elune kind of missing, the NE's souls went straight to the next being close to them - the Jailer?
Or basically Elune could be the mother of life plane while the Jailer could be the father of the death plane.