That was a VERY long read (a little over 1h and a half for me), but pretty instructive with a lot of interesting conclusions, I say
My thoughts on OP's thoughts on ZUN's thoughts
AI stuff
AI is honestly a bit of a boogeyman for ZUN, as UDoALG is pretty much the third (if we're gonna be generous) instance where you have a faction / character that symbolises it in its perfection + capabilities : between the Lunar Capital, Keiki and her Haniwas, and Zanmu here, it all boils down to absolute perfection and efficiency derived from absolute control being considered as a dehumanizing thing that takes out all the fun part in life as well as agency. So thematically speaking, UDoALG isn't necessarily new or unique for the series. Although the Reimu Zanmu parallels and conclusion give quite a bit of human aspect here instead of the usual.
Zanmu and Reimu
Ability wise, I've vaguely suspected her nothingness abilities to be capable of affecting the mind, especially considering Kicchou's performance in UDoALG's story (a massive downgrade compared to her 17 self), but reading what the analysis put together in a more compact manner has made it more of a certainty. Overall, this makes Zanmu and her ability seem like a FAR MORE potent Kicchou, with far more potent and consequential lingering effects. Pre-chapter 28 CoLA lore is such a big achilles heel to me when it comes to this series's lore as I haven't quite caught up nor manage to keep focus when rereading these again (the writing style, maybe ?), so the talk about hierarchy of thoughts is extremely interessting and educative to me, even moreso in the way it's used to explain Zanmu's ability + its influence : she's not just smart, she makes her competition dumber and apathetic (by means of reducing the thought one is capable to the lowest, base level, seeking the comfort of easy certainty rather than the more challenging alternative (definitely a bit like those who view AI generated answers as authoritative) ; and it also seems that those that are "tainted" by her nothingness become more susceptible to her manipulation, if we go by the closing thought observation on the empty underground spirits.
Character and motive wise, there is definitely a lot of things that get missed if you're not familiar with the kanji & terminology used AS WELL as buddhist concepts ... a very complicated character, whose nuances are easily lost in translation (no blame to the translators, can't fault them for not making mu and mu distinguishably more different and meaningfull, likewise for some potentially-heavy-in-implication-having-words-or-symbols-that-just-don't-have-the-same-flair-in-english),
It's been a year and some more since last I read the various UDoALG dialogues, character texts and omakes, my final impression of Zanmu was that of a Mary Sue like figure that put herself between the Beasts and Gensokyo cuz of Sengoku era likeness related reservations on the surface, with the side bonus of wanting her part of the Gensokyo-influence-cake, which I considered as the justification for her true reason for intervening instead (cuz she's selfish and self righteous and think her view is the correct one), but I had to rethink my conclusions with what the analysis brings to the table : IF confrontation with Zanmu (a losing or less favorable one ?) leads to her nothingness creeping inside one's mind and heart, and IF Zanmu is capable of influencing or even downright controlling those who have that nothingness inside of them, then despite her "official" endgame for UDoALG being genuine (quelling the beasts), the true implications of her powers make her far, far more insidious. I've initially considered her wanting to leave her footprint on Gensokyo's history to be something like Yukari towards Eirin and the Moonies, or even Okina towards modern Gensokyo, but factoring in Zanmu's possible true abilities means that she'll have a portion of Gensokyo's population (& important actors) to heavily influence / control at her own leisure. Now THAT would 've been a more serious incident than whatever real estate drame we've got going on.
It's not clear why absorbing a beast youkai would turn her into an oni, but I think it's partially symbolic
This is a bit of an impression of mine, but WaHH kinda gave me the impression that we could draw a triangle that links human, hermits and onis, as in whereas hermits are humans who've controlled their desires to an unnatural extent, onis are those who've givven into them to an extreme extent. Lingering spirits generally have a bit of desire to them, even moreso for the wild and selfish animal spirits such as those in WBaWC, so I wouldn't be too surprised if that helped(?) her into getting progressively becoming an oni. Food for thought, unceratain of the pertinence of my reflexion here, but aside from that, I'm more interested in how Biten, an Youkai, would get close to Oni-fication herself rather than Zanmu.
Final conclusion 1 : the 4th beast faction
Now this is a big surprise to me, and one of the more bolder theories I've seen these last few years. I'd say it would be perfect for the fourth faction to have secretely infiltrated the closing of the WBaWC saga related game, as it would justify them not appearing later. It helps that one of Zanmu's mates is even reliant on traps like what they're supposed to excel at, while the sheer inisdiousness of her nothingness, which permeates the mind, may as well be considered poison for the soul, and a parasite that suck you dry for the purpose of the secret leader (Zanmu)'s ambitions. It's defensible, but at the same time there are still a lot of ambiguousness that work against that theory (would it make sense for example that someone as thorough and meticulous as Zanmu head a relatively small faction as background noise in the animal realm instead of going for broke and vying for supremacy, especially since she's demonstrated her ability to stand over the various Beast Matriarches ? Plus not hailing from the Beast Realm). But yes, a cool and somewhat defensible suggestion. I still hope we'll get a full fledged faction, tho ! (I've always wandered what's the deal with the fish spirits from WBaWC too, I'm am NOT saying they are related to the 4th faction, but they're so common yet insignificant ... we're probably never getting back to them so whatever)
Final conclusion 2
This is definitely my favorite interpretation from the analysis : the massive influx of spirits from the underworld ... yet they feel empty ? A bit weird if you consider that they should be vengeful spirits at large, coming from the depth and all ... shouldn't they at least have some kind of envy or bitterness towards the living ? Plus the language insinuating the emptiness within them, which seems like it could be the handiwork of Zanmu ... I think that the suggestion that the spirit boom being actually the handiwork of Zanmu makes more sense considering previous points brought by the analysis regarding Zanmu's powers and motives. UDoALG is primarily about the Beast spirits's scramble for real estate, but if the various Beast Matriarchs take action because Zanmu made things look as if it's the wild west with lots of land to conquer through the influx of suspicious empty spirits (that are probably under her influence, if we go by the analysis), thereby luring the various Beast Matriarchs into the rat race and try to infiltrate Gensokyo along with the wave empty spirits that Zanmu sent ? That would certainly reinforce Zanmu's position as the mastermind behind the incident this time, and that's without taking into account the possible additional nefarious motive of spreading her "influence" in Gensokyo.
It's an interesting interpretation, supported by the fact that Zanmu pretty much facilitated the various Beast leaders's meeting with their lieutenants before the proper beginning of the invasion. A bit of a shame that this all takes away from their sense of agency ... only question remain whether they were fully under Zanmu's influence straight at the absolute beginning or it's something that happens later.
So yeah a pretty thorough, comprehensive and educationnal analysis of UDoALG, all in all. It's a cool thing to see something like this in a time where you don't see much of these type of breakdowns nor theories. A shame ZUN doesn't give straights and satisfying clears answers, but I kinda hope the new book that's supposed to come in april is gonna give us additionnal information (instead of just fortunes) for the characters involved in this incident. This makes me rethink and change my settled view of UDoALG's story, so thanks and appreciate the hard work.
For you see, my dear reader, the title, 'Unfinished Dream of All Living Ghost' refers to the American Dream. I **** you not.
HMMMM I wonder why it has ended in the land of fantasies and the forgotten
