The White Lantern theory has been a popular theory amongst fans since Blackest Night started...I think there's going to be some serious shaking up in the GL universe, Blackest Night has been their most dreaded prophecy, an event that the Guardians have been trying to prevent happen for centuries and now that it's finally happening I think there are going to be serious ramifications after this is all over and done with...exactly what those are? I haven't a clue. We do know from the Legion of Superheroes that there is only one Green Lantern left in the universe, perhaps this is the event that triggers that.