Oh yeah, I was gonna ask about that. I never actually got that far into Overlord, in part because it seemed to be meandering into "er well I guess the holy guys are evil so he's gonna be all evil and dark at them, but it's mainly to dicks so he's still likeable."
I guess what I'm asking if he ever gets over being a Mary Sue Edgelord
Actually I will say that... it kind of isn't that... so to speak.
It doesn't reverse the trope EXACTLY. Sure the evil looking people are "The good guys" but only in the sense that they are the least evil guys there... and most of the monsters actually could care less about actually helping people... in fact it is a plot point rather than a background detail.
While the "Holy People" are like any knight order in existence who justify their villainy with the trappings of justice, and never for a second does it ever pretend like they could be the real deal, nor do they pretend they are the natural result of a church.
But... this is anime and "Interesting start with a lot of character driven moments and a few hiccups" turning into "All the interesting aspects that made you watch the anime dissolve into a pile of goo while all the terrible aspects you saw at the start turns out to be the real focus".
Honestly I know that most people say you should give an anime three episodes to be good... but at this point I think that is true, but you should skip to around the middle with the sheer amount of dropped premises.
An anime about characters trying to survive in a world where the elements have leaked in from another plane transforming the people and animals into sort of elemental versions of themselves and played with as a sort of analogy for racial and geopolitical tension... turns into say... A Harem about which hot elemental babe gets to sleep with our hero.
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Or here is a REAL anime example
An Anime about a magical version of the British Caste system and the sort of elitism it created using a main character who uses atypical thinking in order to achieve the same effects and thus poke holes into the entire system of have and have-nots and the story of how the system affects him, the people around him, and whether or not he can actually change it for the better... Turns into a God Mode Mary Sue and how he is so amazing and everyone loves him.