The Los Illuminados were a dark cult based in a rural area of Spain that worshipped the ancient Las Plagas parasitic organism, and sought to use the parasite for their own ends
History
The Los Illuminados' plans were initially extinguished by the first castellan of the prominent and noble Salazar family, who prosecuted the members of the cult and had the Plagas sealed away in the very depths of the Salazar Family Castle, in fossilised form fossils. On top of this, the Salazar family somehow possesed the ability to control the Plagas themselves, and this was a necessary component of the overall goal of the Los Illuminados, who wanted to use the parasite in a bid to spread their religion throughout the world and control every being infected with the parasite as a sort of collective hivemind on a global scale.
South Europe Incident
Despite the sealing of Las Plagas, the Los Illuminados would continue it's plans centuries later under the command of Osmund Saddler. The plan set off when Saddler somehow managed to convince Ramon Salazar, the eigth castellan, that his ancestors had commited a dreadful sin in prosecuting the cult and sealing Las Plagas. With Salazar's backing, Saddler travelled to a nearby village and with the help of the village chief, Bitores Mendez, began long and public religious readings directed at the villagers. A large amount were recruited to excavate the fossilised remains of the Las Plagas. However, the parasite existed in the form of spores at this time, and infected the villagers as soon as they were inhaled. Some years later, these same villagers became the first Ganados. Now with some of the villagers under his control, Saddler then infected the rest of the village with the rest of the excavated Las Plagas via direct injection of Plagas eggs. At some point, the Illuminados managed to take over an offshore island base, and organized a private Plagas-infected militia. A heavily armed battleship was also included. They also hired countless researchers such as Luis Sera who studied the parasites themselves, while others conducted genetic experiments with them, producing B.O.W.s such as the Regenerador, Novistador, U-3 and El Gigante.
Saddler's slightly altered version of the Illuminados overall goal involved the capture of the United States President's daughter, Ashley Graham, and infecting her with the parasite. Once infected, she would be sent back to the US (after some "donations") and the parasite would hatch, and proceed to infect the entire US administration, effectively bringing the entire world to Saddler's fingertips. However due to the actions of Leon S. Kennedy, these plans were destroyed and Saddler was killed.
The current status of the cult is unknown, or whether they even exist at all anymore due to the deaths of Osmund Saddler, Ramon Salazar and Bitores Mendez.