Why is music a prominent theme among the antagonists? There is a good reason for that: in ancient times, singing and dancing were deeply linked to the act of performing magic, to the point that in Italian, Greek and Japanese you don't 'cast' a spell, you 'sing' it. This is why the primary antagonist group is an ensemble themed after an orchestra, the Pianist was so devastating and led to the creation of the band of the Musicians of Bremen.
The designers did a real in-depth job when making the symbols for each Floor◊ as they're all references to symbols connected to their respective Sephirah:
Malkuth is also called 'the Gate'.
Yesod's magical vision is the "Vision of the Universe's Mechanisms" and its symbol is the moon. It's also an obvious indication of it being the Floor of Technological Sciences.
Hod's symbol implies knowledge and logic, two things the sphere is known for.
Netzach's symbol both resembles the trophy in the former Safety department and the sphere of victory.
Tiphereth is commonly attributed with the lamen or rosy cross. It was also a thing in the former Central Command room.
Gebura similarly has symbolic attributions of a five-petaled flower note Also note that Gebura is the fifth Sephirah and the sword...never mind that the sword is the weapon Gebura always used and still uses.
Binah and Hokma are complemental in that Binah prominently features the Yoni symbol that also doubled as her earring, and if you look closely at Hokma's symbol, it features the towers that the Record Team room had. Towers are another symbol of Hokma as they're reminiscent of the Lingam complementing Yoni.
Keter has its namesake crown.
Speaking of the Ensemble, in an ironic twist of fate, their (Enemy-only) pages would be a perfect kit to the Floors you fight them on.
The Crying Children's cards focus on Burn and sustain, two things that Malkuth's Floor emphasizes upon. The passives of his page also give plenty opportunity to induce Burn, including when hit. He also has a burn immunity passive, partially alleviating their strategy of getting damaged themselves to earn buffs.
Eileen's cards mostly feature evasive dice, and timely defensive manouevres is something Yesod's Floor will need should their Glass Cannon strategy go belly-up. Her mass attack immobilizes the enemy, which would be a golden opportunity for the Floor to go ham on their enemies without being damaged. The negative effects of certain Abnormality pages (like that of the Singing Machine) that make them suffer more damage if hit can be completely negated if the enemy can't hit in the first place.
Greta's cards are built around bleed and being a Stone Wall, and the former synchronizes especially well with the pages of the Red Shoes, while the latter is a general fit to its overall stability.
Bremen's cards give buffs to allies and one of them even gives healing, making Netzach's Floor do an even better job at sustaining itself.
Oswald's cards (and that of his peers) feature outlandish effects that can be a mixed bag, but this variety usually provides some breathing room by depowering the enemy directly, letting the Floor focus on the more dangerous enemies to clash against.
Tanya's Attack! Attack! Attack! playstyle is a very good fit to Gebura's Floor, and are best stacked upon one beefed-up ally in order to take the most advantage of buffs. Especially Overspeed can be powerful once one stacks all buffs upon that one ally.
The Puppeteer's cards and the one his puppets use are all good Light restore sources, further supporting the good innate Light restore Chesed's Floor already has.
Elena's cards have good self-healing, which Binah's Floor can use to deal with some of the harsh side-effects of their Abnormality pages.
Pluto's cards have a more outside the box way of thinking to it, but Hokma's Floor can play around certain contracts by simply using all defensive cards.
Argalia's cards have the same generalist purpose that Keter has.
In-universe, guns are strictly regulated by the Head, as per what is revealed in the story of the Full-Stop office. Is it any wonder that ranged pages (indicated by a gun symbol out of all things) are a much, much rarer drop compared to the almost omnipresent melee pages?
Most of the prominent Wings use the first letter of their singularity or purpose.
A Corp (the Head): Authority, Arbitration
B Corp (the Eye): Banish, Beholder
C Corp (the Claw): Claw
F Corp (Faeriesnote Powerful key openers that can open any lock or barricade - used by Garion (Binah) as one of her weapons): Fairy
G Corp (Gravitational control): Gravity
Previous G Corp (Genetic splicing): Gene
J Corp (Casinos, Locks): Jackpot, Jail
K Corp (Produces curing bullets for L Corp out of specific tears): Kure, "'K'"ries
L Corp (Lobotomy Corporation, energy production): Lobotomy, Light
M Corp (Produces the moonlight stonenote Stones that protect from psychological afflictions - used by Syndicates and Fixers, most notably the Liu): Moonlight, Mind
N Corp (Nails, Taboo, Canned experience): Nail, Norm, KNowledge
R Corp (Mercenary units, cloning): Replicate, Retaliate
Why does the Head label their gun control laws as an "Ethics Law" that prevents people from dying too easily, despite being the most corrupt corporation within the entire City, having zero compassion for those being slaughtered in the outside world? Because it isn't an ethic law, that's merely a ruse; its true purpose is to make every single killing as bloody as possible.
Why did Angelica, out of the Color Fixers we know the most about, not have any connections to Iori? Because black is not part of the colors that make up purple.
Why was Xiao the only one other than Kali who was able to succesfully manifestate E.G.O? We've seen that doing this is an incredibly hard process with resisting the Distorting Voice, and even after succesfully manifestating E.G.O, one is not exempt from becoming a Distortion anyway. One of the reasons that Xiao was able to do this is because the Liu have the Moonstones incorporated in their clothing, which naturally preserve the user's mind from insanity.
Despite the City being a fairly massive place where Warp Trains are often required to travel from District to District, the City only has a population of roughly below 10 million, based on rough accounts on the Pianist incident that wiped out 300,000 residents of the Backstreets of District 9 (Which would make its original population around 375,000). All the death, carnage, and suffering must have caused mortality rates to be abnormally high and the population density to be abnormally low.
This seems to have been retconned as of Limbus Company, as the population of the city is shown in the intro cinematic to be around 6 Billion people - essentially almost the entirety of the modern population, give or take a billion or two. This actually makes more sense than if there were only a few million people in the city - the lower the amounts of people in a community, the more valuable they are as a labor force, but in reality the average person in the City has as much value as an ant - indistinct and replaceable.
If one pays attention to Tomerry, they will notice there's a large, gaping cut-out mark on their body that looks like as if their entrails were removed. That's probably an indicator of the "Love Town Mom" Blood-Red Night in charge of the operation, since she used to gut people out and control them to kill more people for her.
Philip is insanely difficult to beat when he finally brings out his E.G.O, despite his combat skills being that of a middle-of-the-road Fixer. Why is that? E.G.O. doesn't need any training to use, because it is powered by the user's heart. Philip's E.G.O. effectively wields itself for him.
Why do the Shi Association Fixers you fight in the Library have their HP reduced by a quarter? They are tired and aren't in good shape because they were being bombarded with high-rank quests from Argalia using Thelma as a front.
Why doesn't any battle dialogue comment on the fact that they'll get their wounds healed and resurrected afterwards? Because in-story, they forget this fact, in order to make the battles more grueling. From a developer perspective, this also makes for a wider range of more interesting dialogue. Gameplay and Story Integration at its finest.
The random Abnormalities faced on each floor are revealed to be more meaningful than they first appear, with each of them representing Angela's (and later Roland's) emotional state in the memories triggered during each Floor Realization.
The Floor of History features Abnormalities that symbolizes Angela's rejection and abandonment by Ayin.
The Floor of Technological Science Abnormalities represent Angela's helplessness towards the forsaking and death of her fellow employees being only a tool for the Manager.
The Floor of Literature Abnormalities represent Angela's loneliness and inability to help her fellow Sephirah with the Meltdowns that they suffered.
The Floor of Art Abnormalities represent Angela's desire to live as a separate entity instead of a tool instructed and used by Ayin, then left to rot in the ruins of L Corp.
The Floor of Natural Science Abnormalities represent Roland's nihilism and acceptance of the greed, violence, despair and betrayals happening all over the City after losing the love of his life to the Pianist.
The Floor of Language Abnormalities represent Roland's Roaring Rampage of Revenge against the City that stole his wife, blindly killing anyone he could find that was even remotely associated with her death, including several Offices, Syndicates, even the Fingers, the Church of Gears, and a puppet-making factory that belonged to a man who resembles the Puppeteer's disguise, which got him demoted from a Color to a Grade 9 Fixer.
The Floor of Social Sciences Abnormalities represent how Roland was being denied access to the Nest because of him trying to antagonize a fellow fixer Office (with the operator heavily implied to be Pluto), causing his family to be stranded in the Backstreets, where he left for one final mission before the Pianist attacked his home District.
The Floor of Philosophy Abnormalities represent how Roland's attempt to protect his newly created family ended in nothing but disaster, with the people whom he antagonized or attempted to murder becoming powerful monsters that would join Argalia against him. They also represent Carmen, who was genuinely trying to save the City, but instead brought forth complete Armageddon as the real monster in a City filled with corrupt, bloodthirsty and eccentric killers, despite being none of those. She also baits people into the Library and gets them killed, something that the Apocalypse Bird actually does.
The sole Abnormality present in the Floor of Religion's realization is WhiteNight, which represents Angela's inability to move away from the "script" on her own; even after the creation of the Library, she couldn't possibly attain freedom without Carmen's advice. WhiteNight also represents Carmen, who claims to be capable of curing a disease that no one else can cure, but the cure comes from absolute, full-blown chaos unleashed on a dystopian City that she attempts to save. Carmen also has twelve "Apostles" (Elijah, Gabriel, Michelle, Giovanni, Enoch, Lisa, Kali, Daniel, Garion, Benjamin, Ayin, with Roland and Angela as the "Heretic") who actively unleash the horror of the Library for her, and like WhiteNight's masked form, the Plague Doctor, is said to be so mesmerizing that those who came into contact with her could only see her as a saint.
Additionally, every successful Floor Realization allows Angela or Roland to learn the same lesson that the corresponding Sephirah represented back in Lobotomy Corporation. Angela learns that she can stand up by herself without seeking Ayin's approval (Malkuth); that she always has a choice on how she deals with tragedy (Yesod); that she can become a better person even after all she has done (Hod); that she should keep on living (Netzach); and that she must let go of her past as "the copy of Carmen" to build her own future (Hokma). Meanwhile, Roland learns that life has meaning beyond pure nihilism (Tipereth); that he must control his wrath for the sake of his loved ones (Gebura); that even though he feels shame for his past actions, he should still have faith in the future (Chesed); and that he must face his fear of what will happen should he let go of his vengeful hatred and break the cycle of revenge (Binah).
This is also why they're called Floor Realizations: the floor itself doesn't become more real; Roland and Angela come to a different realization on each floor.
Why is Angela rather fragile when you get to play as her in Keter Realization? By that point, she's human.
The Thumb combat pages focus on gathering Ammunition pages before discarding them for boosted attacks, this generally leads to the player having duplicates of the same page as there are only three different types of ammunition cards. This makes running a Singleton deck using Thumb pages unreliable, as it is very easy for the player to end up breaking their Singleton status as they're gathering ammunition. Which group introduced Singleton combat pages into the game? The Index, which clashes often with the Thumb.
Argalia wipes out the Shi Association's southwestern operations by sending them a series of extremely difficult tasks that eventually wore them out and got them decimated. He is literally manipulating and subjecting them to karoshi aka overworking to death.
The Servant of Wrath's background story features her as a Magical Girl who values fairness and justice above all others, but made friends with an enemy of her world, a gray-skinned Hermit. She shared knowledge of her world with the Hermit in secret, but the Hermit betrayed her as her enemy and sent a group of minions that decimated her home world, leaving the Servant in a state of guilt and blind rage, stopping at nothing trying to kill the Hermit. This is a chillingly close metaphor to the incident that destroyed former L Corp; they trusted Michelle as a friend due to her amiable and kind personality, and she got to learn every secret about it. Unfortunately, Michelle was purchased by the Head, and she reported her findings to her superiors and they decided to send the Arbiter straight into L Corp. Enabled by Daniel just to buy himself time for survival, the Arbiter decimated the laboratory and killed its bodyguard Kali, only to be mortally wounded by her and offed by Ayin himself. The incident left Chesed (Daniel) with a strong feeling of shame and guilt that he can't get over, and Gebura (Kali) reduced to a fragment of her former self mindlessly exerting her anger against fellow Abnormalities, mirroring the Servant's feelings of shame and mindless rage in the betrayal's aftermath.
Furthermore, why does the Servant have a blindfold and is themed around a judge? Because of 'blind rage' that is a result of playing Hanging Judge for yourself.
The Jester of Nihil is presumably either a collective being spawned from the Magical Girls' distorted desires or a separate being influenced by the Girls. In the final phase of Tipereth's Realization where you fight Roland using the Jester's E.G.O., you must awaken the four true Magical Girls - ones that stand by their original, positive values - to realistically put a dent on his massive HP pool. You are literally beating the negative desires that plague the city - greed, hatred/hysteria, despair/apathy and wrath/guilt - away from him using the embodiments of their positive forms, and making him see the hope that everything will change for the better.
With the Black Forest birds (Big Bird, Punishing Bird, and the Bird of Judgement) having symbolic representation of an overbearing and deadly authoritarian government rife with ridiculous Blue-and-Orange Morality, it's no surprise that they're assigned to the floor belonging to one of the Head's former top enforcers, Binah/Garion.
The Apocalypse Bird's story talks about how a person warned the Big Bird, Punishing Bird, and Judgement Bird about the appearance of a terrible monster in their forest, causing them to perform violent acts which led to them becoming the actual monster they tried to prevent from appearing, the Apocalypse Bird. The Head attempted to preemptively prevent multiple Wings from creating Angela by attacking the Outskirts Lobotomy Corporation, resulting in the exact conditions where she would be created and later wreck massive havoc unto the City. Considering how Angela is often compared to a monster by later guests (and is seemingly treated as such by the Head's standards due to her being an A.I.), this comes as nothing short of a Self-Fulfilling Prophecy just like the Apocalypse Bird that is an allegory of the Head.
The allegory of the Apocalypse Bird being Angela, a monster unleashed by the Head, is further proven by how the Library "saves" its guests: baiting them into a beacon of light to get them defeated and booked, just like how the Apocalypse Bird (and Big Bird) baits people into its jaws to get them killed.
On a meta level, it makes perfect sense why Mili provides certain songs for the soundtrack; when people distort/gain E.G.O, they hear a voice. Mili provides a vocalized track for each of their boss fights.
Each of the Abnormalities on Roland's floor can be seen as representing the Reverberation Ensemble members he most directly impacted.
Bloodbath: A creature made from and revolving around blood similar to Blood-Red Night, a Distortion that Roland originally took down.
Heart of Aspiration: Removed organs, one of Pluto's primary tricks as Yesterday's Promise.
Pinocchio: A puppet, who for bonus points in the original fable was treated as the son of its creator, just like how The Puppeteer lost his chance at reviving his own son to Roland.
The Snow Queen: The original fable revolves a boy being taken from his sister by the Snow Queen, just like how Argalia saw Roland as taking his sister from him. Both of them sport primarily white and blue color palettes as well.
Silent Girl: Not directly related to the Reverb Ensemble, but more related to Carmen, the Ensembles real conductor.
How come Angela allows herself to be killed in the ending where she doesn't let go of her vengeance? Because after all that time, she had realized that she was perpetuating the cycle of suffering of her own volition instead of at the behest of someone else. In her own way, she became just like Ayin.
It seems so strange that the members of the Reverb Ensemble would collaborate with each other, given that each of them has a very different vision of an "ideal world". But you need to consider two things regarding their leader, Argalia. One: his charisma is incredible, to the point that his ability to resonate and "reverb" with other people is precisely why he was made a Color. Two: he represents Thaumiel, aka Duality and Conflict. Of course the members of his group would have ideals so conflicting.
Many events that change the course of the story in this game share one pattern: Someone's lover or love interest was killed indirectly by the Voice of the Distortion or booked in the Library in a failed mission, leading to more tragedies happening in a collapsing scenario, with Roland, Lulu, Philip and Xiao being the most prominent victims. Since both the Voice of the Distortion and the Will of the Library is Carmen, this is not surprising. In her first life, Carmen was both on the giving and receiving end of this by being crippled over the guilt of killing Enoch, Lisa's (platonic) partner and attempting suicide only to be skinned alive by Ayin. She probably knows best why Love Hurts, and is projecting her traumas upon the Cityfolk.
Knowing just how the mechanisms of the Library work raises the question as to how Philip could escape at all, not once, but several times. With the revelation of who is the force behind the Library, the answer becomes more clear. Carmen deliberately let Philip leave un-booked specifically to allow him to 1) bait more Light-bearing groups into the Library and 2) have his E.G.O. trigger, then Distort. The emergency teleportation device that Oscar put on Philip was probably purposefully redirected to the 8 o'clock Circus by Carmen to force him to fully Distort and become a useful pawn to hand over to Argalia so that he could further guarantee his success when the Uninvited Guests finally break in to use the light in case Angela got cold feet.
Ayin, Adam, Argalia and Angela all have similar characteristics:
All of them have a name starting with "A": Ayin, Adam, Argalia and Angela.
All sought to harness the power of a Seed of Light for various reasons: Ayin wanted to cure the City's citizens of their "sickness", Adam wanted to free humanity of their "shells", and Argalia wanted to cure the City's "loneliness". Angela initially wanted to become human and enact revenge on the City for her suffering, but in the good ending she changes her mind and uses the Seed to free everyone who died within the Library.
All of them follow the will of Carmen in some way or form. Ayin and Adam both want to fulfill what they believe was Carmen's true vision, while Carmen herself guided Argalia and Angela under the guise of the Voice of the Distortion and the Will of the Library, respectively.
All of them embody the concept of Kether, "Unity". Ayin unites and uses all the lessons learned from the Sephirah Meltdown (which represent the other nine parts of the Sephiroth) to defeat his Literal Split Personalities. Adam claims that he "knows all" thanks to transcending his own humanity. Argalia is True Companions with his fellow Ensemble members despite conflicting ideologies, and seeks to unite the City by unleashing Disotrtions and E.G.O.ists all over it. Finally, in the good ending of Library of Ruina Angela and Roland forgive each other because of the lessons they learned from the Floor Realizations.
All of them also embody the concept of Thaumiel, "Duality/Conflict". Ayin caused a lot of the conflicts that happened during the series, and eventually split himself into multiple personalities. Adam is one of Ayin's personas, and his ending causes the City to be thrown into chaos. Argalia has multiple contradicting beliefs - most notably how he was driven to despair by Angelica's death, and yet he worships the Pianist who killed her. Finally, in the Foreword ending, both Angela and Roland cling to their desire for revenge, and reject the lessons of the Floor Realizations.
All of them guided a group composed by the other nine parts of the Kabbalistic Sephiroth and/or the Qlipoth. Argalia has his Reverberation Ensemble, which represents the latter; while the others have the Sephirah, who initially embody the latter but later switch to the former.
All of them led their own group against another group that embodies the opposite concept. In Lobotomy Corporation, Ayin (Sephiroth) had to fight against the Architecture Department's Sephirah Meltdowns - which reuse the gimmicks of previous Meltdowns (Qlipoth). In Library of Ruina, Angela's Library (Sephiroth) and the Reverberation Ensemble (Qlipoth) end up facing each other near the end of the game.
Finally, the final challenge each of them had to face before obtaining the Seed of Light is a fight against a Foil. Ayin and Adam had each other, while Angela and Argalia had Roland. In the good ending, Angela also ends up facing against Carmen, the person she's a copy of.
Fridge Horror
In an interview with Project Moon, they reveal that the Pianist, from all the horror and wreckage it causes, would be between WAW and ALEPH if it were an Abnormality instead of a Distortion (sort of like King of Greed or Judgment Bird); very powerful, yes, but still somewhere around a WAW. If something like that was a WAW, it's pretty clear that L Corp has been keeping (and often suppressing) unfathomably dangerous things that would blatantly cause an apocalypse if they were ever unleashed onto the outside world, a scenario that can be seen to begin in Ending C of Lobotomy Corporation.
Keep in mind that in L Corp Abnormalities are fought with Qliphoth Deterrence inside the facility, indicating that they would be much weaker and manageable than usual, and employees will still have trouble dealing with certain Abnormalities anyway, especially some WAW-tiers and most ALEPH-tiers. The Library has the Abnormalities severely weakened because of the Seed of Light, but they are still strong enough to defeat your Librarians. So if these things were to be released into the wild...good luck.
Why does Angela get noticeably grossed out when she witnesses Tomerry? She's subject to the exact same singularity that drove the Warp Train's passengers insane in a 2,000 year torture, perceiving time 100 times slower than the L Corp, which is already affected by the slowed time zones. Angela is probably having traumatic flashbacks to the horror she was programmed to suffer back there.
Ayin's management methods aren't simply dubious and unethical - it's simply monstrous beyond all belief, on a level unlike other Wings. From outright killing Enoch and Giovanni to driving Angela to despair when she was once just as nice as her human counterpart because she isn't actually Carmen in Ayin's eyes, he's reached a level that puts even the Head to shame. (He himself actually admits it on Day 48 of Lobotomy Corporation) Pretty much the only things saving that man was he genuinely did all the sacrifices and horror for the sake of altruism to the public and he actually does express genuine love.
In Lobotomy Corporation, the Rabbit Team alone is capable of creating a massive Zerg Rush within the L Corp facility. But in this game, there are only a handful of R Corp troopers raiding the Library in each of the three teams (and they can be beaten realistically by your librarians, whereas a fight between an agent and a Rabbit in the previous game would always end up with the agent dead). That's because they use L Corp's energy to mass manufacture clone troopers, but L Corp's collapse greatly broke their economic basis. R Corp is most likely just standing on its last legs without the help of L Corp. This is further compounded by R Corp also arranging a portion of their troops to L Corp's former nest, hence the significant drop of personnel deployed to the Library.
Just how scary the Head is? Look no further to how many of their agents we know that are named despite every person in the City knows perfectly that they exist and the consequences of procuring their intervention; one. Yes, one out of a Shadow DictatorMegacorp that nobody even knows in-detail. This agent is Garion, an Arbiter who carried out the (narrowly) failed raid against former L Corp. It's possible that nobody ever survived a hostile encounter with the Head, and L Corp is most likely the first entity that somehow managed to survive one and tell the tale.
On another point, in an interview with Project Moon, they were asked about what would happen should Ending C of Lobotomy Corporation come to pass. Their answer? That the Head would deal with it. While they didn't elaborate on it, the implications are there, the Head is prepared to deal with multiple apocalyptic monstrosities. And it's possible the Head may even emerge victorious.
As it turns out, the Head, also known as A-Corp, are the ones who handle the patents for the various Singularities of the Wings, both current and fallen, as well as selling access to them to those who have enough money to pay for them if no one owns them. This means they have access to all of them, including the one from L-Corp. Which means they have their own personal access to Cogito, and by extension, Abnormalities. It's no wonder they are prepared to deal with multiple apocalyptic monstrosities, if they can first deal with them in a controlled setting. And considering they have access to every single Singularity that has ever existed within the City, they may evenknow how topermanently kill them.
Cue the epilogue, and an actual Arbiter comes to invade the Library alongside the first on-screen Beholder and the first named Claw (again not an Ordeal, a real one), who is also a superior unit known as an Executioner. Needless to say, a Library that ran out of energy to fight any longer (because of being whittled by both Reverb Ensemble receptions and Roland, as well as having ejected most of their defense mechanisms after confronting Carmen) has no footing against them and the whole Library was instantly ejected back to the Outskirts. The scariest thing is that, absolutely nobody knows how many Arbiters and Claw Executioners they still have after this.
Bear in mind, the three people who were there to oppose Zena and Baral were Roland, Gebura and Binah. Roland and Gebura, two of the strongest known Color Fixers, and Binah, a former Arbiter herself (who in this fight in particular had inexplicably regained all of her lost strength). Granted, Roland was tired out at the time through his own fights against the Reverb Ensemble as well as his own reception, but still- considering these were the absolute strongest people the Library had, and how they could only hold the line until they were ejected... the implications are scary.
Just how evil you are portrayed in the game itself? Look no further than Phillip's arc. First, after Oscar placed an escape button on Phillip and he flees after manifesting an E.G.O., only to jump right into the 8 O' Clock Circus spider's parlor and the "voice of a woman" turns him into the Crying Children Distortion, then it lets one of the angels flee and he destroys his former home district. This led to the Liu Association taking the task to slay Phillip and raid the Library, causing most of the association's Southern Branch to perish within the Library, and its section head Xiao being corrupted by the enlightenment of the Library to the point that she manifests a proper E.G.O. before she dies as well. The Library is most likely deliberately ejecting Phillip into the 8 O' Clock circus and sparing him so it can cause a chain reaction that will cause more deaths and create more books from those who were hapless enough to infiltrate it.
Something about Book of the Red Mist, which portrays the beginning of the end of Outskirts Lobotomy quite succinctly and accurately, from the eyes of a less biased person. It might sound weird when Carmen was obviously showing signs of suicidal depression and coming to work looking like shambling death, the rest of the research team enabled her to isolate herself and did basically nothing against it. They were most probably waiting for her to attempt suicide so they could extract her for Cogito to further their research.
At the final act of the Syndicate's arc, it turns out that the Prescripts are somehow serving the Library's interest instead of the City's interest despite the fact that they come from the Will of the City. This leads to many Index and Thumb members dying inside the Library, which itself displays some sort of self-awareness. The Seed of Light might have made its way into the Will of the City to poison the Prescripts for the Library...
Compare Plague Doctor and WhiteNight's flavor text in Lobotomy Corporation to how Carmen was often described, and many things are similar between both entities.
Both Carmen and the Plague Doctor claim that the world has contracted a dreadful illness that only they could cure, and are seemingly altruistic beings who take delight in helping those who suffer.
Just like how the Plague Doctor is said to be doing all sorts of miracles, Carmen's behavior completely violates the City's logic (such as wandering in the Backstreets alone while getting out completely unscathed or being able to captivate most people just by convincing them).
Both had effectively created a Cult around them, as seen from how Daniel, Kali, and Ayin couldn't find anything shady or bad about her to begin with after interacting with them personally, even if Daniel and Ayin were elites and Kali is a skeptic around Backstreet crazy cults.
Both of them have twelve Apostles that were redeemed from the City with the 12th being a heretic within them, and they actively use their Apostles to unleash an unprecedented catastrophe. The description of the Paradise Lost weapon mentions WhiteNight staying in this world for a moment, but kindling the path of light, just like Carmen who didn't last long, but left the way for an unprecedented City-destroying disaster.
There is no documentation of WhiteNight being anything else than a pure being that has come to be a savior, similar to how Carmen effectively was Loved by All.
WhiteNight tells his Apostles that they will abandon flesh and be reborn again and transforms them into monstrous Apostles, while Carmen deliberately invokes incidents that would turn people into Distortions. And last but not least, both Carmen and WhiteNight have unnerving pure white skin and red eyes.
◊ as they're all references to symbols connected to their respective Sephirah:
