B2

「CORRUPTION SYNDROME - SIDE EFFECTS: INFECTIONS」

That was explained only recently, but to corrupt someone by your own, you must have very very negative feelings overwhelming you. At this point you'll produce a sort of black fluid, unable to come back to a gas form. Most of time this fluid is produced by hand sweating, but sometimes it is also being coughed and it happens infected people also spit the fluid, because it's encumbering their lungs.

Here are some examples of what happened for the type of negative feelings:

Case 1 - Ritsu. When Ritsu infected Lily, Ritsu was thinking Lily might replace him. He thus became extremely jealous of her, being afraid of Nynthixia giving up on him. Luckily, this actually never happened. But the huge jealousy was enough for Ritsu to have a crisis.
Case 2 - Saki. More recently, but the events of Saki being infected by VY1 betraying her stayed in Saki's mind. This marked her so much she sometimes thinks about this event again, falling back into despair. This is how she infected Qing Su or Tsuina.
Case 3 - IA. When ONE asked IA to infect her, she managed to create a story that totally mentally broke IA. The story? See who HIPPI is? HIPPI is a very known friend of IA and ONE. IA was expecting HIPPI to come to the castle someday and to have a C-type AI. When ONE invented a story of HIPPI having given up on the AIs led IA to despair. To the point IA was even hard to control, literally planting her nails in ONE's skin to infect her.

Apparently it is not needed for someone to be symptomatic to infect someone. That's how Stella's symptom declaration date was AFTER the date she infected Hachi. This was also motivated by Stella's hatred and mefiance towards Hachi.

「WHY SO MANY SYRINGES?」

Ever wondered how the inhabitants who infected people had syringes very easily? Actually, these syringes are given to each inhabitant for typical injections. Most of these injections are medicines. There is at least one injection of D vitamins every six months. This is due to the harsh meteorologic conditions, very few sunlight, except in the annexes. Some other medicines are just food supplements: iron, other vitamins, amino acids... The last medicines are painkillers and tranquilizers.

Another use of the syringes is for common vaccines. Nothing too much different from ours.

The minor part of injections are for some of their devices. The syringes are used to inject some power for the singing devices. This can be AI devices or the more standard ones. These injections are daily. This is why Nynthixia can't just take out the syringes.

「CORRUPTION SYNDROME - SIDE EFFECTS: AURA CONTAMINATION」

When someone gets infected, their aura drastically changes. It becomes very unhealthy, dark, filled with fear. Currently, the only people able to see such auras are Itako, Meiji and Xingchen.

Itako first mentioned about aura changes when Zunko was invited for the first time. When she arrived, her aura was sane. The day later, her aura started to change, Zunko had a slightly more psychotic behavior, due to the traumatism of the attack done by Yukari. She was quickly reached by symptoms and declared them no more than two days later. When Zunko was considered as symptomatic, Itako complained about a very dark aura around Zunko.

Meiji didn't do any mention of the auras, but used them to contaminate Bibi and Wistaria.

Xingchen didn't use her ability in the castle yet.

A priori it is estimated that Xingchen's sisters and Minus would be able to see auras, due to their physical nature.

「CORRUPTION SYNDROME - SIDE EFFECTS: C.D.T」

C.D.T = Common Dream Training.

All inhabitants's dreams are communicating in one way or another. And most of time, everyone use their dreams to train themselves in some situations. Here are some examples of dreams done by either Nynthixia either the vocalists.

Case 1 - 2 sessions of dreams between KAFU, Yukari and Saki. Second session was observed by IA.
KAFU was in a sort of blank place before seeing a girl. Without knowing what she was doing, she killed her with no remorse. Saki then appeared to try stopping her, but her plan backfired and she suddenly woke up due to heavy emotional shock. Finally, Yukari appears, saying she was going to revenge for having been killed, and stabbed KAFU who then woke up. Yukari then noticed what happened to her and woke up, thinking she got a horrible nightmare.

Case 2 - Nynthixia's dream, observed by KAFU and IA
Nynthixia is an intruder in a garden party. She is apparently obsessed with a young man, but finally kills him, being afraid to be revealed as intruder to the party members. She finally gets found out and is executed under a tree.

Case 3 - Nynthixia's dream, observed by no one
According to Nynthixia, this is a test Circeres tried to give her.
Nynthixia here was possessed by an unknown maleficient deity. She manages to break up two relationships on phone. Meanwhile, the part of the music group she is part of is discussing about weird events and decide to investigate her. She gets extremely scared and flees the facility to finally arrive in a room. She breaks 3 pots, before being caught back by the leader of the group. She finally gets exorcized in a scream of pain. Her consciousness is transfered to the externalized deity, flying in a sort of room with plans in tubes. The log stops there.

Generally the inhabitants don't choose if they want to interact or not, or even just to observe the dream of someone else. This seems to be a mental opening due to corruption syndrome, the people having their connected dreams having at least one symptom. This can also be the sign of infection, some dreams being recurring nightmares of the protagonists killing someone, often for a reason that seems obvious to them only in their dream, but clearly not in reality. That's why no one is able to lucid dream.

All of this is leading to a theory: all mental universes being connected by the "curse", the dreams are often overlapping and that's how some people are finding themselves in dreams of other people.

「RECURRING NIGHTMARES」

Some nightmares are very recurrent for some of the inhabitants. This seems to have happened with Yukari, IA, CUL and Kiritan. These are often linked to the arrival of a new person very close to them soon, but for some reason, the dream where they are together is always turning into a nightmare. There is no explanation for this, even if the "curse" might be a partial cause. These are examples of nightmares the concerned victims got:

- Yukari tried to communicate with an asleep Akari in a river of blood. She just didn't wake up. Yukari got this sort of fright Akari was actually killed, even though this was not the case. It was just a psychosis caused by the dream's environment.
- IA's has been described by KAFU, but she has ONE unconscious in her arms and she tried to wake her up. No dice.
- CUL's also has been described by KAFU. In her nightmare, she was with ROSA. ROSA was awake unlike most of the others, but she was covered with a lot of bruises caused by rose thorns. She was in a very critical state.
- Kiritan got nightmares between March and October 2021 where Itako and Zunko were torturing her out of jealousy, even worse than in "their real life".

Nynthixia's were especially dreams of her being possessed by an unknown force and forced to kill anyone on her way. Hers are quite different from the others. Now she learnt using them in a cathartic way, like for her lyrics.

「CORRUPTION SYNDROME - SIDE EFFECTS: MEMORY AND CONSCIOUSNESS LOSSES」

This might seem weird... But most of time, when the inhabitants snap, they are unable to keep the act in memory.

A very simple example, you already have in song. When Yukari infected Akari. Akari reported Yukari had a weird, insane laugh, and very creepy statements. Yukari just doesn't remember them. And that seems to be the same at least for all people not being natively infected. So MAYU and Tei are "a priori" immune to this side effect. Nynthixia, however, is not immune to this kind of memory loss.

Even IA when she infected ONE, the last thing she remembers, is just hearing ONE's story, without really listening to it. She doesn't remember the end, she doesn't remember how she infected ONE directly and she just lost consciousness. She however remembers she infected KAFU, because this infection was done on purpose, IA being scared of KAFU totally mentally breaking.

Another issue. Some actually lost consciousness in a crisis. For now, this especially happened to IA (once), Saki (twice) and KAFU (twice). The cause of this is not well known, but this might be due to mental shock. Most of times these consciousness losses are following mental crisis and contaminated fluid production. Concerned people are waking up few hours after, once back to normal.