I think i figured out what that means!!!
Orochimaru used it to revive the 1st and 2d hokage.
On wikpedia it said that Kazuma could use some sort
of "revive and control" people jutsu. It was called Tensei.
So maye Pain (pein) killed some people, and revived them to work for
him. :confused: Maybe...
Edit: The part when he used it to revive the deva is also a part of what i meant.
I think the reason deva realm was still injured was because of the lack of time to
revive it fully.