Powerful I will probably grant you, though Evil Bob did almost take Dresden if wiki isn't lying to me. But knowledgeable is very arguable. As I said, within Bob's skull is knowledge enough to kill gods, create a new fae court and probably more.
Evil Bob almost took Dresden in Dead Beat because Dresden wasn't expecting it to be hostile. And in Ghost Story Ghost!Dresden was much less powerful than his normal alive state. Bob is a mini-Archive in a setting where knowledge is power; he's surprisingly powerful, but not powerful on the scale of the bosses like true naagloshii.
The naagloshii is explicitly thousands of years old.
Bob's recorded history is less than a thousand years; by his own tale in this AU, he wasn't there/alive for Mab's ascension, which hard caps his age, and we know canonically that the skull he inhabits was made around six hundred years ago. That gives you an age range between six hundred and a thousand.
Sigrun Gard is older than he is.
Yes? That's all information relevant to wizards.
Its not exactly news to spirits and Fae that Halloween is when true immortals are vulnerable, or that ascension rituals like the Darkhallow are a thing.
Literally an ascension ritual by a spirit was the plot of the Dresdenverse comic Welcome to the Jungle.
And Mikaboshi became a Yama King and created his own Hell much the same way; he was originally human.
Wizards, especially young wizards, have a tendency to assume that a lot of things that are new to them are necessarily new to everyone else, instead of just being things not discussed in polite company, or that is restricted until you are a level of power or need.
Its like Dresden finally telling the Mothers about Nemesis, and their reaction being "Oh, so you FINALLY saw what was in front of your nose this whole time?"
Thanks. I knew all of those except Madeline and Madrigal. So, we can surmise that Black Council (or at least forces associated with them, or at least forces associated with outsiders) were involved in our initial kidnapping (if I recall correctly, canonically this might have been a ploy by Mab). Maybe as a ploy to get someone infected into a Knight of the Cross's vicinity? We can safely assume that "the kidnapped victim breaks out with an Infernal Exaltation on her brow" was not the initial plan (unless, like, there's a hidden Maiden behind a curtain, and/or some of the First Age beings really are back and are retroactively messing with causality). Harry was involved in our rescue.
The presence of the naagloshii doesn't seem to be directly connected to the nazi plot, and was mostly incidental there. An attempt to study us in combat against something close to a peer opponent (Katrina had perfect effects, and was a divine spirit and a seer and a sorceress with near a thousand years of experience)? That's why Harry was attempted to be removed from equation. The naagloshii seems to be mostly here because of White Court.
It confirms that Nemesis was involved in our initial kidnapping.
I always thought that it was more they were following orders from Infected Maeve, but if Eldest Fetch was also Nfested, thats a more direct connection.
Either way, we were a convenient target, because Infected!Maeve's plot is aimed at convincing Summer Lady Lily that Maeve was on the up and up, and Mab is the one who is crazy/Nfested.
Which yielded fruit several years later when Maeve convinces Lily to help her attack Demonreach.
So part of the reasoning is Molly = Dresden = Lily.
Mab had her own aims, but we dont know what that is.
Whoever arranged the naagloshii's presence would have been planning for it for months if not years before our Exaltation. So the naagloshii being here isn't linked to us.
White Court plot by the Black Council. Not the only time they do it in canon; they do it in White Night and Turn Coat.
If the Eldest Fetch infected I don't see why the other are not also infected unless he was infected the same day he died.
The inconsistency on nemesis infection has always been weird. Like why Thomas's girlfriend and not Thomas himself.
I just generally assume that there are unclear rules restricting it. Maybe you can only infect people during the full moon or in a place of desolation or the person you are infecting has to say a certain word unprompted or really anything that makes it so they can't just infect anyone at will.
Because Nemesis has limits on how many people it can infect at the same time, and so it has to pick and choose.
And I think human rules about free will probably apply to Nemesis as well.