All right, I've got a crit.
>>Since the story involves a lot of [Comedy] (using sarcasm, wit, and cultural misunderstandings), [Adventure] (Luna and the Mane Six literally travel across five continents, though mostly for brief periods as their aboard a Preußischer ship, the K.M.S. Jericho), and gets [Dark] (non-grimdark references to the horror of war; a German-based state that is really an army that owns a state; daemons; an in-depth look at how religion can reflect a culture, and how affects religion can have on a population; a close-up look of patriarchy and how it effects every culture, especially that of Preußen and even Equestria; OCs [and only OCs] getting seriously hurt; the OC narrator is and honest-to-God sociopath, and said trope is deconstructed; and all occupying a moral gray-area where there is no good or evil, no true right or wrong, where there is only who wins and loses) – and they all happen about evenly, often within the same chapter. (And it's not grimdark, I swear.) What am I supposed to tag it, then, since these three tags work with it as well as can be?
Just because a story contains some comedy and some dark aspects doesn't mean is actually needs those tags. Many stories contain some humor, but that doesn't make them true comedies. I went and saw the Hobbit and there were plenty of jokes in it, but would I ever call it a comedy? Sarcasm and wit do not a comedy make. Think about it like this: if someone walked up to you and said they were looking for comedy MLP fics because they needed a good laugh, would you recommend this fic? It doesn't sound like it. And if the level of comedy really is high enough to make this fic worthy of being called a comedy, I would be very concerned that all of the dark elements would cause mood whiplash in the reader.
This fic looks like it will be fine with just the [Adventure][Dark].
>The Ezsett "ß" isn't about me being exotic so much as that's how the word it spelt, because I could Anglicize it as eighty "Preuszen" or "Preussen", by the would fundamentally change how the word is pronounced, to the point of being unrecognizable in verbal communication. Is it still okay to include the ß when it's the only way to ensure the Latin-spelling version of it is pronounced correctly?
The ß will ensure it will be pronounced correctly? Maybe for people who know the original language, but for anyone else it's just going to be an incomprehensible symbol. If this fic is for English speakers, then the name should be pronounceable in English. I'm sure readers would rather have a technically incorrect Anglicized name they can pronounce than a correct one they can't pronounce at all.
I come from a land far to the east, a place called Preußen, a nation of proud stallions. Who I am doesn't matter. What does matter, however, is the cultural dissonance between our two peoples, those of Equestria and those of my homeland. What matters more is how I, by virtue of being at the wrong place at the right time, am now entirely at the mercy of these naked Equestrian savages. I am by no means the hero of this tale, and this is hardly even my story. I'm just a nopony thrust into the Equestrian world, with their strange customs and way of thinking. To them, I guess, I'm just as alien, with my so-called barbaric language, strange God, and cultural need to wear pants. Oh, and let's not forget how the Prince of Darkness and the Biblical Kane are waging a war for the fate of the whole universe, and how I get forced along by sheer virtue of me being able to translate from my language into Equestrian. This is the story of culture, language, and six annoying yet special girls with their lunatic princess saving the world. Oh, and I guess I'm along for the ride, too, since I'm the narrator.
The first issue I see with this is that it's too long. Shorter is better for summaries.
Second, the narrator. You write that this character isn't that important, and that it isn't his story even though he is narrating it, but the main characters aren't mentioned until the second to last sentence. Luna isn't even named. Most of this summary consists of his thoughts and feelings, without revealing much of the plot. If I were skimming over this, I would assume this was a story about the narrator stallion dealing with Equestrians, with the stallion himself as the main character. The main character in the story is the one with the problem to confront and solve. Right now, it looks like this stallion is that guy.
The stallion can still narrate the summary, but the focus needs to be on the main characters and their mission. Speaking of which, what is their mission? Apparently there's a Prince of Darkness and a Biblical Kane, and they have to save the world. We know that the narrator feels compelled to wear pants, but we have no idea what the actual problem the heroes are solving is.
Here's an example summary to give a sense of what I mean. I just made up details for purposes of example.
'I have nothing but disgust for the ponies of Equestria and their strange ways, but when demons plague my homeland and signal the coming of the legendary Prince of Darkness, the Bearers of the Elements and their pagan Princess of the Moon are our only hope. With me as a translator, they journey to the nation Preußen to destroy the hidden temple and prevent the Prince's ascent. But seven Equestrian mares must overcome more than black magic in a land ruled by clothes-wearing stallions who worship very different gods.'
Obviously I filled in a lot of random details which probably are totally inappropriate for your story. However, it might be useful to look at this as an example of cutting down the word count and getting to the meat of the story. Note how this was shorter than your original summary but contained more specific information. Also, even though the narrator is a distinct presence, the quest of the main characters is front and center.
Here is what you should try to get into your synopsis:
1. Who are the main characters of this fic? In this case, it would be the Mane 6, Luna, and the narrator. The narrator can be introdu
ced though the overall tone of the summary.
2. What is the problem they are trying to solve? They're off to save the world or universe or whatever, but why is the world threatened?
3.How are they going to solve it? You don't need to go into every detail of the plot, but give us some sense of what they're specifically trying to accomplish.
4. The culture clash is obviously a very important plot thread, so you need to get that in there. You didn't have trouble putting it in your original summary, but you could probably have implied the culture clash in less words to save room for other important plot points.
Hope this is useful. It looks like you have a very creative premise on your hands.