though another theory of mine is it could also mean the espers will save humans again.
since this story follows the biblical events, Michael being the angel that fights evil, that means that theres something more intense and powerful than the espers and i dont think its the "angels" theyve already defeated i think it might be their "father" God, or more concerning his "twin brother" Lucifer with who Michael leads an ultimate war with.
theres also the fact that the person who raised Michael (lets call him the highest rank, but not godly) is paired with Gods strongest and most reliable angel Gabriel, but I havent come up with what that could mean yet
UGGHH I LOVE WHEN BWAT COOKS
When he goes berserk from Adam dying, getting hurt or something, he's gonna use his "children" and this Sync thingy to unleash the wraths of hell unto earth.
I CAN SEE IT FROM A MILE A WAY. Not a spoiler btw, just a theory. A Yaoi Theory.