one of these days its going to be revealed that they were blessed by some ancient bloodline or that they were just faking it all along and that they really are angels or something....
They are bumbeling around abit too much even for this type of manga.
It'd be so much easier to care about this fight if the initial plot contrivance of the MC's mana being drained without his knowledge wasn't such a break of my suspension of disbelief.