The Gray Curse

The Gray Curse, also known as the Plague of Metals in more academic circles, is an illness that has the unique characteristic of slowly transforming living creatures into beings of metal. The process is very slow, often taking months to begin showing visible signs of change, and can take entire decades before the victim has been fully converted. Mortals fear it above any other illness, though thankfully the demigods have been proven to be uniquely immune to its effects. The true danger of the plague is not in the mortality rate however but in what occurs after the disease has overtaken its host completely.
The infected rise again. A twisted amalgamation of flesh and metal. Less living beings and more walking machines that have grown within the infected and slowly overtaken their host from the inside out. The leftovers of the original owner of the body is left hanging loosely from the metallic skeleton that now wears it as a tattered suit.
Once newly risen the original infected seems to lose all higher brain functions. They roam around breathing and eating to carry on what little biological functions they still must attend to and are anything but discerning eaters. Fortunately they are typically slow and clumsy and mostly subsist off what they can scavenge. On rare occasion they have even been seen to cannibalize one another to survive for a few more days. More concerning is the fact that there is no struggle. One simply lays down and allows the other to feast upon it.
That is, of course, under normal conditions. When the infected accumulate in larger numbers they gain an uncanny sense of coordination. Not just working together but moving as if they share vision and thought like a single large, living being. Similarly they begin to move with a surprising purpose. Cutting off enemy escape routes, forming pincher maneuvers, even setting traps with wounded foes as bait. Even their individual coordination improves as they go from shambling creatures to being able to sprint and even fight with a degree of animalistic coordination. Between the physical augmentation their new metal forms provide and the enhanced coordination they display the shimmering hordes are among the few forces in the Churning World that absolutely demands the attention of a demigod to deal with. Fortunately they are quite rare, but when they do occur no mortal force has any hope of contending with them.
The metal first begins to form around the bones. This greatly enhances the strength and durability of the infected, though they will not know immediately what the cause is and may not notice the effect as it is gradual and occurs over the course of a year. Then the metal will begin to become visible externally. Primarily it will be visible by coating the fingernails and newly grown hair follicles first. Then slowly spread out from the extremities until it covers larger and larger sections of skin. After a few decades the infected will be wholly covered in metal and their internal organs will have been largely transmuted as well. Eventually the victim will die from being unable to survive the extensive extra weight and medical complications from having portions of their insides turned to metal, at which point they will rise wholly transformed into their new state of being.
The exception to this normally slow process is when the infected has been injured. The normal healing process is accelerated and what should be new tissue will be metal instead. This can occur as early as six months after being infected and is an easy way to catch the virus early.
Those infected by the Plague of Metals are typically banished from their communities out of a combination of pity, mercy, and fear of infection. Those with the Gray Curse often form their own communities on the outskirts of civilization far from the uninfected where they live out their lives knowing they will one day become a monster that hunts the innocent. Usually these communities watch over their own and agree to destroy each other’s bodies so that this cannot happen.

Transmission & Vectors

The first step to combating any illness, even one as unique as this, is understanding how it can be transferred from one body to another. Fortunately it is quite hard to accidentally be infected by the Plague of Metals. During its early stages the virus can only be transferred by blood. The curse, as it is called, resides inside the body for the first year or so before clear signs of the metal transmutation begins. Once metal begins to show heavily on the body however the virus will have moved into other bodily fluids such as saliva and sweat making physical contact with the individual dangerous.

Causes

The exact cause of the Gray Curse is unknown. Many common folk believe the Metal Eaters to be the origin of the virus due to their own metallic bodies. This, of course, is not true. Merely a superstition thought up by the ignorant. What is known is there seems to be a malevolent force in the blood itself. When observed through a god’s-eye magnification scope we can see small, gray, cell-like organisms that move through the bloodstream and slowly convert other cells into their own kind. In this way we know it to be a virus, though admittedly unlike any other virus known to the demigods and seemingly driven by some demonic intelligence.

Symptoms

The first sign of being infected is a simple, unhealthy pallor to the skin as nutrients are taken from the body to facilitate the slow transformation. Infected will likely feel tired and weak even while technically gaining far greater physical abilities than they previously did. After a year the metal begins to become visible around the extremities, which is a surefire way of determining someone has been inflicted by the Gray Curse.

Treatment

The only known treatment to the Gray Curse is death. Specifically death within the first year. Unfortunately few mortals are willing to end their lives so easily. Especially when faced with such a slow progressing illness. Once metal begins to show however it is often too late for a conventional death as they will rise from the grave after a few weeks. To truly destroy the infected the body must be burned and metal melted down into slag.

Prognosis

First Few Months: Slowness of the body and a feeling of perpetual fatigue and weakness. Gradual weight gain with no indications of growing fat.
Months Five Onward: Tissue damage is healed with visible metal rather than newly grown skin and muscle.
First Year: Enhanced strength and durability due to now metal-coated bones and enhanced muscle tissue. Beginnings of external metal tissue around fingers.
Second Year: Fully metallic hair and nails. Teeth begin getting coated in metal as well.
Third Year: Skin starts to get transformed started at the extremities and slowly growing down along the fingers, toes, feet, and hands.
Fourth year: Hands and feet are fully transformed. Metallic nails become claw-like and teeth become more jagged and sharp.
Fifth year: Metal begins to spread out from around one or both eye sockets. Veins in the arms and legs start to become visibly metallic. Blindness sometimes occurs.
Seventh Year: Metal will have spread in vine-like growths along the face and arms and begun effecting the throat. Any metallic scars will also have spread through the body in a similar way. This stage has roughly a 14% mortality rate.
Tenth Year: Metal begins to interfere with internal functions. May cause difficulty breathing. Extreme soreness is common by this point as the body suffers from many obstructions in normal movement and function. Body is roughly 20% metal. This stage has a 42% mortality rate.
Fifteenth Year: Body is now 40% metal. Whole limbs are metallic and muscle tissue has been largely converted as well. Metallic spines begin protruding from the body and sometimes causes severe skeletal misalignment. Brain damage is possible due to metallic growths within the skull. 67% mortality rate.
Twentieth Year: Large sections of the exterior is covered in the metallic growths. Roughly 60% of the body has been replaced by metal leaving very few functioning organic systems left. The original personality of the infected has likely been altered to some degree due to the virus moving into the brain. 98% mortality rate. Very few survive passed this point and usually only through divine intervention at the hands of a demigod.
Twenty First Year: Death. The virus at this stage seems to attack the heart directly so as to kill the host so it can reanimate them. There is no known way to prevent it.

Hosts & Carriers

Though the Ironfolk are not the origin of the plague they can sometimes be carriers of it. Because of their ever growing need for metal to reforge their components the Ironfolk will occasionally scavenge the corpses of those infected by the Gray Curse. It is, after all, the only renewing source of metal in the Churning World.
When they do this the metal they harvest may still carry the virus on it depending on what methods they used to reforge or clean the metal. It is rare but not impossible for their blades, claws, or teeth to infect mortals with the virus as a result should the mortal be cut.

Prevention

There are two methods by which one might protect themselves from the Gray Curse.
First: Be a demigod. The children of the gods seem wholly immune to the infection which is of great fortune to all. Likely it is a result of the virus being unable to thrive in their divine blood. The mortal descendents of the demigods seem likewise resistance, though the more distant the relation the less resilient to the plague the mortal seems to be and very little study has gone into just how much divine heritage one needs to survive.
Second: Do not get infected in the first place. This involves staying clear of the infected and not exchanging any bodily fluids with them under any circumstance.