The Ray Field Plague was a lethal disease that originated from radiation poisoning from Ray Field energy, the energy force left behind by the Ray Sphere. After the Ray Sphere was activated in Empire City, the plague struck immediately and killed nearly all of the city's inhabitants.
Some of the infected were reported dying the same day they showed symptoms of the illness. Those who had their Conduit genes activated were unaffected, rendering them immune to the disease, while normal humans died. After an encounter with John White, Cole MacGrath gained the ability to see people that have been infected by the plague via his Radar Pulse power.
It started striking the population soon after the blast. It's highly lethal. Some folks die the same day they show symptoms.
― John White's observation of the sickness, as it took over Empire City.
The plague came right after the devastating blast at the Historic District of Empire City. The disease caused several civilians to become terminally ill and rendering them virtually paralyzed. The plague struck most of the populace at Empire City, and it inconspicuously and slowly made its way across the country, infecting millions of civilians.
It was later revealed, through Dr. Sebastian Wolfe's notes, that the plague was caused by an overabundance of Ray Field energy among the area. The most notable way that Ray Field energy was scattered on a wide magnitude was through a Ray Sphere Blast. It was later discovered that Conduits, with their abilities and powers activated, are virtually immune to the effects of the disease, as they show no clear signs of the common symptoms. Only normal human beings and dormant Conduits, whose powers have not been activated, are affected by the plague.
The disease is known to be very fatal, as several civilians and voices are heard saying that there is no existing cure, and they cannot formulate a cure due to the disease's unnatural structure.
Not knowing what to do, the government's initial plan of action was to put the city under quarantine while they look for a cure. Left with limited options, the government and any other parties were rendered helpless due to the fact that there was no cure. The only known counter-measures could be done by Cole MacGrath and only two are plausible: curing the plague at the cost of the Conduits lives including his own or turn humanity into Conduits with odds of 1 to 1000.
- Main article: Good karma#Endings
Sebastian Wolfe, a researcher of Ray Field energy, developed a device called the Ray Field Inhibitor to cure the plague. With the energy of a Conduit strong enough to contain the power of the device, it created a powerful signal great enough to break through the atmosphere and sent a surge of energy all across the world. The signal cured those infected with the plague, killing all who bore the Conduit gene, dormant or not. After absorbing seven Blast Cores, Cole MacGrath was able to charge the RFI enough for it to function and eventually cure the plague. However, it was later revealed the RFI had not killed all Conduits, just most of them.
World of Conduits (Non-Canon)
- Main article: Evil karma#Endings
The Conduit John White ravaged most of the East Coast by using his powers to activate the Conduit gene, thereby making them immune to the plague. Consequently, all civilians near John without the gene die from his method because he became a "living ray sphere." Seeing this as the only possible way for life to outlast the plague, John asked Cole to help him. Cole agreed, but John eventually wanted to stop this method since it involved taking the lives of many. John, knowing that Cole was capable of carrying out the plan, transferred the former's powers into the latter. Cole, with John's power, became the Beast and continued to transform the world into a world of Conduits.
It is hypothesized that the plague had mutated after the RFI went off and created a new Conduit gene in people.
- By the end of Infamous 2, a news report from USTV stated that the plague has reached about halfway across the country with no known cure as of yet.
- After all the main missions in Infamous are completed, the USTV broadcasts said that the CDC had developed a vaccine to cure the plague, “with a 99% success rate and administered with a single shot”. This is referring to the military invasion of Empire City, seen in End of the Road and Infamous (comics).
- The plague is caused by ray field radiation which is caused by a Ray Sphere blast. Cole takes blame over causing the plague. However, Bertrand is to blame for the Plague in New Marais, as he detonated a prototype Ray Sphere within the city's limits decades before the Empire City blast.