Necroa

Most Deadly Disease
Concepted and created by Death, then improved upon in the current cycle by Pestilence, Necroa is the ultimate disease. It is entirely created using power that is not of the Earth, though for the most part it adapts and behaves like a disease should. It can enter the body through any opening, be it the mouth, the nose, or open wounds. Its vectors of transmission mostly include already infected hosts, as the disease survives only a few minutes without one. Areas with highly concentrated Ley and other magical sources, such as Equestria, see longer survival times. It has a 100% fatality rate.

Symptoms
Within minutes of infection, hosts begin coughing. Their eyes receive a slight mutation, four yellow dots arranged in an upside-down trapezoid around the iris. The top two dots are large than the bottom, giving the appearance of butterfly wings. Within the hour, it spreads to the host's digestive tract, converting the bacteria that usually reside there into additional Necroa cells, causing blockages and pain as food is unable to be digested. In the next few hours, the rest of the symbiotic bacteria, such as those in the mouth, kidnies, etcetera become infected, and the host is able to transmit the disease to others through his breath and fluids. After approximately five hours, Necroa beings attacking the brain, destroying and converting brain cells as needed. This causes memory loss, siezures, paranoia, and severe dementia as it spreads. Hosts usually become psychotic and incoherent after six through seven hours, and will descend into a dangerous rampage that can potentially spread the disease if they are allowed to roam free. Death occurs after approximately eight hours, and they are immediately risen as a zombie to serve Death.

Very soon after death, Necroa hijacks the lungs and recommences breathing, converting the taken oxygen into more Necroa cells instead of carbon dioxide, which it then expells as a normal breath. Any open wounds between the lungs and the mouth may also emit the miasma. The infected air is a clearly visible black, and anyone caught inside it will become infected without proper protection. Because of the dependency on the hosts, these clouds disperse and die within a minute of being expelled. The remnants of the host brain that was converted now functions as the life support, and as long as it is intact, even the head alone will continue serving Death. Additionally, the skin cells become reinforced against the elements, making them more resistant to natural hazards. This allows them to cross hot deserts and freezing tundras without issue.

Necroa also converts the bacteria responsible for decomposition, greatly slowing the rate that the hosts deteriorate.

Prevention
There is no cure for Necroa.

Necroa mutates at an alarming rate, and does not survive in lab conditions, making cure research nearly impossible. Additionally, as it is directly controlled by Death, he is able to kill it whenever he has no further use, so the few hosts that do get captured are not able to be studied for very long.

Necroa is also very formidable. It is immune to all known antibiotics and antiparasitics, magical and otherwise. It is very resistant to magic, and only the most powerful shields will prevent it from entering. Because of its magical origins though, Necroa will survive significantly longer attached to said shields. Non magical protection, such as gasmasks and hazmat suits, are considerably more effective.

They are able to survive conventional weapons as well. Firearms, explosives, and the like will not kill Necroa, neither will environtmental hazards such as burning or freezing. However, they might destroy the host, which will cause the death of the Necroa cells anyway.

Immediate removal of infected areas is a slim possibility. The speed of its spread usually renders this useless, with less than a one percent success rate. Inducing blood clots, Necroa's main form of transportation in its first stage, can increase survival odds, but this is very dangerous if the one performing it doesn't know what he's doing.

Fat tissue somewhat slows down Necroa's progress, as it can clog arteries and generally take up space. Obesity can lengthen a patient's survival time by a few hours, if it is severe enough.

Other highly aggressive diseases, such as malaria and some cancers, slow the spread of Necroa. In some cases, patients last up to twenty four hours, instead of the usual eight. However, it is still a 100% fatality rate among them.