I'm finding this really interesting. Finally connecting some dots... although I've forgotten lots of the dots. I think I should re-read since we're finally (if slowly) getting new chapters.
And let me mention I'm sure this isn't a result to the popularity of other world genre. This series was always the sort to have a lot of foreshadowing. It began long ago and the author couldn't work on it for a long time for health reasons. Certainly she was thinking during that time. This chapter would have been planned long ago. Plus it isn't entirely clear the world of the Noah's isn't the very Earth from long ago. And think about it the Flood Myth... the entirely of humanity destroyed by God. The world swept clean... except for one family. But in this case the truth is it was the pillar, and that family despised God for what he has done. Thus not really an other world.
@Meita
I think that theory is interesting but incorrect. I think the Earl (despite his mental issues) knows exactly what he's doing. It might be that he's being used, but that doesn't necessarily mean he's being tricked. I think he's rebelling against his own destined role, and corrupting the very souls he's supposed to "save" as a means to this end. I'm pretty sure I vaguely remember "something" that says the Earl isn't the Heart, and neither is Allen. It is someone in the Black Order.
But those pictures...
IIRC that's when Allen ran himself through with his own sword (harmless to humans?) but destroys Akuma. What's that in the background? That's no coincidence...
And the current chapter