I think the main problem with this kind of story is that every time, a new villain is introduced as OP and the top of their field (here, the headmaster was a war hero and whatnot, and the new guy seems to be a genius of some kind that was able to repel one of the OP characters easily), all that to discover once they are defeated that there is something above we didn't know about, and the defeated villain was actually trash.
It works a few times, but as the pattern repeats over and over, the meaning of power just gets lost, and the story becomes dull.