Plaga or Las Plagas (Meaning "The Plagues" in English) were an ancient and unique kind of parasitic arthropod rediscovered under the castle grounds in a remote part of Spain owned by
Ramon Salazar as recently as the 21st century in their fossilised form. These were genetically re-engineered and enhanced in laboratories operated by
Osmund Saddler, a Bio-Organic Weapons (B.O.W.) researcher who saw their potential as a weapon and as a source of wealth. If the right kind of B.O.W.s could be created, they could then be sold to the highest bidder.
It's possible that Plaga also originated in West Africa, as they have also been recently found there but this cannot be confirmed.
Many different types of Plaga were created, including various Lesser types, more Dominant species and a larger Queen Plaga which had the ability to asexually produce more.
Osmund Saddler eventually founded the
Los Illuminados as a cult group and eventually had enough influence to take over the entire region of Spain where they were settled. He along with
Ramon Salazar and
Bitores Mendez were all implanted with Dominant species Plaga and had the power to control all other people infected with lesser Plaga who were known as
Ganado. Once the area was completely under a single banner, the cult moved forward with a plan to take over the world, firstly by capturing the then-US Presidents daughter
Ashley Graham. The plan would be to kidnap her, inject her with a Plaga, turning her into a
Ganado and return her to America where she could then systematically convert everyone else she came into contact with.
Plaga infection cause various mutations and changes to it's host. How to control these is not clear, but many experiments were conducted in order to produce various creatures such as
Ganado,
El Gigante,
Regenerador,
U-3 etc. They all vary dramatically due to different steps taken when they were being created.
One of the key researchers in the Plaga experiments, Dr. Luis Sera became disillusioned with the cults behaviour and attempted to break away and escaped his facility with a Dominant Plaga egg, which he was instructed to pass onto H.C.F. (Hive-Host Capture Force) operative
Ada Wong in exchange for his protection.
Leon S. Kennedy who at the time worked for US-STRATCOM was dispatched to the area once intel was received on the whereabouts of Ashley. He conducted his mission thoroughly and happened upon many different kinds of hosts infected with Plaga, all with completely different abilities, strengths and weaknesses.
There were four known types of Plaga. The original found in Spain, and then three further genetically modified versions which were all found in Africa, all created by TRICELL. The main improvements over the original was that a Plaga infection could only take place if an egg was implanted or injected into a host, where it would take several days to mature and even longer to grow to an acceptable strength. In the future versions, a mature Plaga could make direct contact with a host and take over it's body and cause mutations instantly.
Also, a Plaga is usually not seen in it's host unless the body is attacked in such a way where it feels it needs to protect itself. When this happens the parasite will emerge from the body in some way - usually the most convenient place at the time, for example with a
Ganado if the head is destroyed, it will sprout from the neck and take over the body in order to attack. Or with an
El Gigante, it will emerge from open wounds over the creatures spine, where it was initially implanted. It's worth noting that
Leon S. Kennedy discovered that lesser species Plaga have a weakness to blinding flashes of light, as a Flash Grenade destroyed them instantly.
Interestingly, Plaga resemble creatures from horror movies, such as the Facehugger from the Alien franchise, and also the titular Thing from The Thing.
