I mean
Dies Irae is the kind of series that would unironically use the words "outerversal" in its own script from what I understand.
So that's a fair reaction
It’s actually been grossly exaggerated by bandwagoners. I know because I read the whole thing when it was finally translated.
Literally the entire verse caps at City level in feats and about MHS for its whole run safe for the very end of the final route.
For an idea of how hard people wanked it, you know how Reinhard’s Longinus spear was wanked as this beyond impossible, faster then the concept of speed, Gae Bolg on roids attack?
It’s just fast and the statement that it’s like Schreiber whose speed is always +1 the opponent is contradicted later by that lightning Nazi chick Beatrice being faster from being well… lightning fast.
However, at the very end of the last route, the series suddenly jumps into Multiversal territories when the protagonist, Reinhard, and Mercurius achieve Atziluth and have a battle across the entire universe, destroying and recreating it in their own images, warping reality, Yata Yata.
Specifically, one or two of Mercurious attacks affects the entire multiverse at once and both the MC and Reinhard survive it.
EDIT: Oh and Mercurius has been remaking and resetting the entire multiverse over and over out of sheer boredom, every route basically being one of these past realities. And by the end, Reinhard and MC-kun scale to him.
But that’s the most you get from it
www.fanverse.org 
