The Corrosion

The Corrosion is a administered blood disease, presumably developed by the Royal House of Cards, and administered to others by the members. The development, as well as the purpose and goal related to it currently remains unknown to the main player characters, save for those who have characters involved with the House.

History
Next to nothing is known about the process of the Corrosion's development, its history, and the like. Thus leaves a few questions questions:
 * Who developed the Corrosion, and why?
 * How long has it been in development, and for what purpose?

Purpose
The purpose of the Corrosion remains complete unknown. Why the House has infected both Caroline and Dr. Tominaga, as well as Ezra and other children, is a mystery. Due to the lack of light shed on the topic by both of the infected teachers, the Corrosion's purpose for existence is unknown to the players.

Identification
The Corrosion is very easily identified, and is not exactly a challenge to spot.

It is primarily identified as a darkly coloured viscous plasma, and seems to be very prevalent in any environment.

Administration
The Corrosion seems to be something that is, confirmed by Dr. Tominaga, only able to be administered into a person's body, and is not an infectious disease. So far, the Corrosion has been observed to be administered in two ways. How the Corrosion can shift forms, or other methods of administration, is currently unknown.
 * Direct ingestion (Tobi getting 'new medicine' from their mother).
 * A powdered form being hidden in pills, and consumed via direct ingestion (Dr. Theodore K. giving Caleb pills with the Corrosion in it.)

Counterparts
In the Progress Report, Dr. Tominaga mentioned a King Counterpart, though what exactly the counterpart is, how many other counterparts exist, and what their purpose is is yet to be revealed canonically.

"Corrosion Worm"
The Corrosion seems to take a unique form in Heightened Perception, sometimes seen as what is described as a 'worm'. It is seen predominantly in Ezra's heightened perception between himself and Azoth, in which case the worm was seen in a glass aquarium, being held inside. It was dubbed Woomy by Ezra.

It seemed to have a consciousness, as it actively made attempts to free itself and was able to recognize Ezra when in close proximity, and seems to have some sort of power as well, as it was able to procure enough force to knock over the glass and finally free itself.

Information Leak Countermeasure
A more recent mechanic introduced into the game and into the timeline, those infected with the Corrosion seem to possess an inherent inability to speak of it to other individuals, because of the possibility of a leak in information regarding it.

The mechanic was implemented soon after Dr. Tominaga was confronted by Ruby, Oliver, and Caelum, in which he discussed a multitude of details regarding the subject, and was somehow sensed by Spadille, who then in turn implemented the mechanic as a countermeasure.

In numerous attempts, Caleb tries to communicate his problem to others, though is largely unsuccessful in his endeavours. How Dr. Tominaga was heard (?), or known to have said information regarding the Corrosion remains a mystery, and how Spadille could directly change the mechanics of all infected individual is never revealed.
 * Speaking of it causes his jaw to clench and he is unable to move his mouth, making any attempts to speak of the Corrosion to other individuals a futile effort.
 * Writing also seems to be a problem, as the handwriting becomes near illegible.
 * He has picked up sign language, though whether this will be successful is yet to be tested.

Causes of Progression
Based off of the Progress Report, a few assumptions can be made based on what was written.

The Corrosion seems to be an infection which mainly affects the blood, and seems to 'corrode' RBCs. It seems to diffuse into the bloodstream via ingestion, and then attach itself to RBCs, and multiplies and spreads throughout the body by being pumped through the cardiovascular system. As the blood cells are infected, oxygen intake is compromised, causing the heart rate of an infected individual to naturally increase to make sure that oxygen intake is secure.

This naturally leads to fatigue and lightheadedness, as well as a general increased heart rate. This natural response of increased heart rate causes the infection rate to increase. In addition, the added viscosity of the blood would cause the BPM to increase in retaliation, adding to the increased infection rate.

Early-Onset Symptoms
Not much is known about the early symptoms of the Corrosion, though has been given to others as information to properly portray their characters correctly. These symptoms include the following: These symptoms have been observed to carry on even in later stages, sometimes with more intensity.
 * Headaches and feelings of head pounding
 * Increased heart rate
 * Drowsiness or dizziness
 * Fainting and light-headedness
 * Feverishness and higher temperatures
 * Thirst or parched throat

Stage One
Corrosion, at stage one, has been seen to have a few notable symptoms. It is characterized as the first stage of the Corrosion infection, having many physical outwards changes in the body, which makes itself very obvious.

Coughing and Black Bile
One of the primary and most telling symptoms of the Corrosion at Stage One is the Black Bile.

The Black Bile seems to make itself known when a carrier of a strand is under high stress or pressure, triggering a spike in heart rate, causing the infected individual to cough, which oftentimes causes the Black Bile to rise and be expelled from the body. It stains easily, and seems to take a very viscous form.

"The Blackening"
Something called The Blackening (as stated by Dr. Tominaga in the Tobi Dinh Progress Report) is apparently a symptom of the Corrosion, though what exactly this is is never elaborated upon in the report.

Compromised Heightened Perception
A way that one can identify the Corrosion's influence on themself is the status of their Heightened State Perception. The Corrosion seems to take form in HSP as a blackish purple goo, coating the spirit's world, and is often needed to be suppressed by any spirit to their host.

This can be observed when Socko attempts to hide the Corrosion infecting Tobi's spirit world, and when Azoth actively tries to stop the Corrosion from escaping in Ezra's spirit world.

Blood Infection
In the Tobi Dinh Progress Report (done shortly after it was understood that Tobi contracted the illness), a few points seem to come out. These implicate that the Corrosion is a disease which infects the blood more than anything.
 * Erythrocyte Count - Count is lowered.
 * Blood Viscosity - The viscosity of the blood seems to be slightly more dense.
 * Blood colour - Blood colour has been observed to be darker.

Stage Two
Stage Two has yet to be observed in canon, though Caroline has been through stage two.

Stage Three
Stage Three has yet to be observed in canon, though Caroline has been through stage three.

Stage Four
Nothing is known about the symptoms which carry over from Stage One to Stage Four, though Caroline still coughs up black bile, though Masque's world has not been described as anything overtly effected, questioning the Corrosion's effect on the spirit world in Stage Four.

However, Caroline has been depicted to have black or dark purple veins all over her body, likely directly correlated to the Corrosion, but in which stage this occurs is not known.

Other Stages
The only documented knowledge about the Corrosion stages is up to four, observed in Caroline. However, whether or not the stages extend remains unknown, as Caroline is the only on-screen character with late stages in Corrosion, and other infected individuals have not been seen nor identified in canon.

Victims
It is implied that the Corrosion has infected others, but the only known members of the main cast that have been infected and have shown symptoms are the following: Other named victims have not been presented nor identified, or have not shown visible symptoms.

Other Infected Individuals
Any other infected individuals are few identified, though it has been implied that others are infected. In a single scene, Spadille has been observed to actually drink the Corrosion, but why he would do so, and why it doesn't seem to affect him negatively is under speculation.

Fun Facts

 * There's nothing fun about poisoning children. Don't poison children, it's illegal. You'll go to jail.
 * It has been made a joke in the server numerous times that the Corrosion is actually just black licorice, hence the tar-like viscosity, as well as the colour.
 * Woomy is just a reference to the sound "woomy" made by Inklings in the Nintendo video game franchise Splatoon, implying that Ezra plays it.
 * A few words to describe the Corrosion have been disease and illness, though in prose has been referred to a poison, so the actual identification of the Corrosion has been ambiguous at best.
 * A majority of the server seems to make the Corrosion synonymous to a poison, when this is in fact an inaccurate observation, in terms of how the Corrosion functions, and its purpose.
 * The Corrosion is based on concepts from the Corrosion Campaign, in terms of appearance, but most (if not all) mechanics have been changed for the purpose of the Aprilside Campaign, as well as for the purpose of the mechanics of the Paranatural universe.