A more recent WOJ leaves it ambiguous about lower-order angels. Archangels being top-tier are not though - I specifically think this was to in relation to whether Lucifer had been infected by Nemesis, and Jim was shutting that down. It seems the Prince of Darkness is beyond such things, and is evil for his own reasons.
That said, I could understand if regular angels simply thought they were immutable. Same for all immortals.
The point being, Nemesis breaks the rules about immutability because it is so powerful (being a Walker of the Outside - I use that phrasing because Jim does most recently, which suggests being a Walker is more powerful than a normal Outsider). But Archangels seem to be just as powerful so perhaps that's why Nemesis can't infect them.
Ethniu herself might not have been infected by Nemesis (assuming she could) and I doubt she bowed her head to any being in the last few decades or centuries even. That said, Nemesis says the Outsiders "unleashed the primal forces of your Creation against you" - that is for sure Ethniu. Ethniu being an original member of Creation (perhaps even proceeding it, depending on how you look at it).
I'm pretty sure there was a WOJ that, at least, archangels aren't susceptible to Nemesis because their nature is immutable. Maybe he wasn't speaking to the lower orders of angels on that point because he just wanted to keep readers guessing, but the omission seems striking.
On the other hand, it's not impossible that some of the Fallen - being treacherous by nature - might make a calculated decision to go over to the other side for rewards under the new Outsider order, rather than being compelled by Nemesis. Or the infection might be of the host rather than the Fallen.
Regarding Namshiel though, I think he's the misdirect, with Tessa and/or Rosanna framing him as the Denarian turncoat. Marcone isn't an innate talent, or at least he's a very minor one if he has any juice at all - most of what he's doing relies on Namshiel's power. All it would have taken to ensure Nemesis' success in BG would have been for Namshiel to turn off the tap at the crucial moment. That suggest that while Namshiel is still a dick, he's acting on his own purposes rather than the Outsiders'.
As for Arctis Tor, we don't actually have Mab's reasoning for believing he was the attacker (for that matter, she didn't actively confirm Harry's guess that he was, either, she just stayed silent to it). But I don't think it would be beyond Tessa's abilities to cast a disguise that would pass for Namshiel so long as she didn't get too close to Mab. Just choose a spiny battle form instead of her usual one - or even cast a high quality illusion of one - fry some foot soldiers from a distance, and boom, you've got a patsy set up even if the attack fails.
Besides, on all the other occasions we've seen Namshiel fight, he seems to have a preference for more esoteric forms of magic over raw fire - I suspect it's an egotistical streak. I suppose it's possible the attacker really was Namshiel and he was just resorting to crude fire because it's a good counter to lots of Winter troops, but it seems more compelling that someone less talented was posing as Namshiel.
Agree with pretty much all of this.
I am curious how Namshiel allows his hosts to become such powerful sorcerers so quickly. From what I understand, the Fallen can't really given you anything you don't already have. They just show you how to tap into power you already have and nurture it. That said, Jim has been
very inconsistent on the Denarians over the series. Certainly early on they seemed to be super-powered terminators. It used to be that it took decades if not centuries to turn a minor talent into a major one (I think that's said in Death Masks). Yet Marcone in a few short years (half a decade or so) is doing more complicated sorcery than Harry. He might not be as strong as Harry, but he seems WAY stronger than he should be. Which makes me wonder if Marcone had untapped talent or if Namshiel is simply understands sorcery so well he can transform any talent into a powerful being very quickly (perhaps even has special gifts in this regard).
I do really quite like the idea of someone setting up Namshiel for Mab to be angry at (along with the other Denarians) and Marcone paying the price, despite neither he nor Namshiel actually being involved. I am not saying it's actually what happened, but it would make for compelling reading.
They are I believe the same thing, the Outsiders split when they disagreed with creation, the Fallen split over the rise of humanity.
In that case the Hosts of the Fallen are already nemfected.
Do you believe Angels, Fallen and Outsiders are actually all the same beings? And you must also then include other primordial spirits that then became known as gods and monsters that existed before Creation began. Interesting idea, thinking of them all as simply different factions. And could well be correct. That said, Outsiders do seem to have a qualitative difference to every other being. But perhaps that just because they live Outside. I mean, you have to be right to some degree. Any being that proceeded the beginning of all Creation (the creation of the multiverse) is sort-of an Outsider, because that seems to be all there was Before Creation. Although it wasn't Outside "back then" it simply was everything that was.
Not sure it's what Jim has written. But I don't mind the idea at all.
I suspect this is the case because I don't think the fallen can be Nemfected directly.
Remember the Winter Lady wasn't infected (the mantle) rather the host was infected. Killing the host removed the Nemfection (or Molly is Nemfected...).
Keep in mind that the Outsiders didn't want Ethniu to win, they wanted her to do damage and distract Harry so he would let one of them into the Well... the plan REQUIRES Harry to ultimately win and when Marcone could have turned traitor to let Ethniu win... the Outsiders wanted Ethniu to lose. So while I agree that Marcone and Namshiel are NOT Nemfected, I don't think this proves anything.
This can't be. All the outsiders work together (as near as the council can tell) with one will.
If the Outsiders were originally Angels and they split from the white god during creation and then later a second group of Angels split from the white god because he favored humans (with free will) they would be two distinct groups with two distinct goals and thoughts (as indicated by them splitting over different issues and at different times), they could cooperate the same as a host and Denarian can cooperate, but the fallen would not be Outsiders any more than Uriel and his crew are Outsiders... they would be three groups of Angels (Outsiders, Fallen, and Angels).
I agree that it's probably more likely the host is infected rather than the Fallen. But it wasn't so long ago on this very forum (and just about every other Jim Butcher discussion forum) prior to Battle Ground being released that most people firmly believed mortals COULDN'T be infected by Nemesis (despite rather clear evidence to the contrary, and the fact that Lily said revealed it in Cold Days). Only seeing an infected Justine convinced people. That said, there is a WOJ that deliberately is ambiguous when asked whether a Fallen could be infected. I can find it for you if you want.
Not so sure that the Outsiders didn't want Ethniu to win though. Nemesis talks about it being less of a plan than "an act of faith" in empty night. Nemesis seems to be a bit more Joker than Bane. Agents of chaos after all. Because say Ethniu did win, it would have left Demonreach undefended, and the Outsiders could have attacked the island just as they did in Cold Days, and no one would have been there to defend it.
Nothing to say Marcone isn't infected just yet. But not much to say that he is. He still seems to be acting the same way as he always does, which would suggest he isn't infected.
Why couldn't multiple spirit beings infect the same host? Harry has had more than one being in his own head! Unless I misunderstand you. Not saying I agree with CT's theory altogether, although technically all beings from Before Creation are Outsiders of a sort. Just seem to be vastly differing types!
The Outsiders definitely wanted Ethniu to win. She was there to kill Mab who's the leader of the forces guarding the gates.
And you've got it backwards. The Angels were originally Outsiders. The angelic faction is the splinter group that serves their leader, TWG, and helped form Creation.
Forgot that key part, but quite right. Mab being dead would have made for a very weak Winter - hence Mab's request to Harry.
There does seem to be some qualitative difference between those beings that are referred to as Outsiders, and other spirits from before Creation such as angels and gods. They all do seem rather familiar with each other though, certainly no love lost.