Prime universe
(Capcom's primary storyline)
See also: Plaga Type 2 and Plaga Type 3

Plagas (プラーガ purāga?) are a genus of macroparasites native to Spain, where they are known as "Las Plagas", itself a borrowing of the Latin word meaning "plagues". Plagas can use various animals as hosts such as dogs, though they are more known for their parasitization of humans, who are referred to as "Ganados" or "Majini". Plagas typically take over the host's nervous system so as to take control. However, due to the repeated attempts to genetically-modify Plagas for use as a bio-weapon, the exact relationship between Plagas and their human hosts varies.

Los Iluminados, a Spanish cult with undefined connections to bio-weapons circles, was the first organization to seriously research the Plagas, of which they genetically-engineered at least two new subspecies: one which could influence decisions of the host or even hijack its body, and a second, the "Dominant subspecies", which would instead issue commands from its host to the other subspecies, and would mutate the host's body if necessary. This allowed a hierarchy to form, wherein a small cluster of people chosen to harbour the second subspecies would be able to control the others. Research on Bio Organic Weapons was derived as a consequence of research into the Plagas' effects on the human body.

TRICELL Africa is known to have obtained samples of both subspecies, which were further modified upon and cloned to create three new species of parasitic bioweapons. The "Type 2" would hijack the human host akin to Los Iluminados' research. "Type 3" was a modified "Type 2" with genes spliced from Los Iluminados' Dominant subspecies. "Type 3" therefore behaved the same as "Type 2" in taking over a host's body, but also mutated it. The third species was a mutant Dominant Plaga, of which only one is known to have existed.

In the years following TRICELL's research, Plaga development was continued by third parties. During the Eastern Slav Republic's civil war, there were another two subspecies, taking hold similar tendencies as before. One was a subservient Plaga subspecies that would hijack the human body, placing them into a Zombie-like state without consciousness. The second was another Dominant subspecies, able to issue commands by the host to the others. However, an intentional flaw in the Dominant subspecies' design was engineered, wherein it would eventually hijack the host's body and make them act the same as the others.



The Plagas were first discovered by a religious group known as "Los Iluminados" (The Enlightened Ones) in an unknown, rural region of Spain. The cult used the parasites as a means of recruiting new members; however, the first castellan of the Salazar Family vehemently opposed the cult and sealed off access to the parasites in his castle.

Centuries later, Ramon Salazar, the eighth Salazar castellan, was convinced by Osmund Saddler, the new leader of Los Iluminados, to join his cult and break the seal that contained Las Plagas. The two then hired local villagers as miners to extract the parasites.

Fossilized Plagas

Fossilized Plaga

Due to years of confinement, the Plaga parasites initially seemed dead. Some were later found fossilized (which was once believed to take millions of years) in the rocks below Salazar's castle. However, despite this, there were still living Plaga spores within the fossils. The miners that were hired to excavate the parasites inadvertently inhaled these spores, allowing the Plaga to grow within them and eventually take control of their bodies. Since then, Saddler was able to recreate the parasites wholly, injecting them in egg form into any potential host.

Leon, Ashley, and the Third OrganizationEdit

The 3rd Organization learned of Las Plagas sometime in 2004, when Ada Wong intercepted a desperate e-mail from Saddler's chief researcher, Luis Sera. Albert Wesker tasked the rogue former US-SOCOM operative Jack Krauser to infiltrate Saddler's inner circle in the hopes of acquiring a Plaga specimen. Although Saddler did not trust him, he gave Krauser a Dominant Species Plaga in exchange for his assistance. Saddler wanted to kidnap Ashley Graham, the daughter of the US President, to convert her to Los Iluminados and subsequently infect her father upon release, allowing him to begin his conquest of the world. Krauser, as an American who had worked on Government missions before, was considered the perfect candidate for Ashley's abduction.

Sera openly betrayed Saddler and his cult, removing the parasite egg from his body before it could hatch. In response, Saddler's men kidnapped Sera and held him captive in an old farmhouse on the outskirts of the village, intending to inject him with another egg after the effects of the medication he took wore off. Leon S. Kennedy, an American agent and survivor of Raccoon City who had been sent by the US government to find Ashley, later rescued Sera after finding a note detailing the location of "the prisoner" (as Leon had assumed that this "prisoner" was Ashley), although they were apprehended immediately afterward by Village Chief Mendez, who used his super-human strength to knock them both unconscious. Saddler took advantage of this opportunity to inject Leon with a Plaga egg. As soon as they escaped confinement, Sera stole a Plaga sample (which they needed to infect the US president) from Saddler, who later tracked him down in Salazar's castle and killed him. Leon, in turn, killed Chief Mendez and Salazar, along with the majority of the village population, castle cult members, island militia, Plaga infected B.O.W.s (including Del Lago, El Gigante, the Verdugos, etc.), and eventually, Saddler himself. Although Leon did fight and defeat Krauser, he was unable to kill him. Instead, he is later found and killed by Ada. Leon and Ashley later managed to rid themselves of the parasites in their bodies via a machine built by Sera, and after defeating Saddler, escaped the self-destructing island via Jet-ski. But before they could leave the island, Ada took the Plaga sample from Leon by gunpoint.

Ada, who had hitherto feigned loyalty to Wesker, betrayed him and sent over a normal subordinate Plaga instead of the Dominant Plaga sample he requested, delivering the latter to an unnamed "organization" that she was loyal to. Nevertheless, Wesker later retrieved a sample of the Dominant Species Plaga from Krauser's corpse.

Uses in bioterrorismEdit

Wesker, in cooperation with Tricell, took the Plaga samples he retrieved from Spain and developed them further, creating Type 2 and Type 3 Plagas. They would infect the civilian population of Kijuju (a fictional country in West Africa) with Type 2 Plagas to gather field data on their effectiveness, and to slow down any BSAA agents who might interfere with their plans. Unlike regular Las Plagas, Type 2 is administered orally (i.e., it is forced into the host's mouth) in its matured state, as opposed to injecting a potential host with an egg. This enables the parasite to take control of the host's central nervous system within a matter of seconds, whereas the original Plagas required several hours to several days to incubate within the host and take over its body. Inhabitants of Kijuju infected with this parasite were called "Majini" (Swahili for "evil spirit"), and they would be encountered and fought by Chris Redfield and Sheva Alomar during their hunt for bioterrorist Ricardo Irving. Type 3 Plagas were created by injecting Type 1 Plagas with a gene from a Dominant Species Plaga, hoping that it would enhance the host's physical capabilities while still rendering them susceptible to control. The Ndipaya, an indigenous tribe of the marshlands near Kijuju, were infected with Type 3 Plagas by Ricardo Irving, who told them that it was a vaccine against a (non-existent) disease.

During the Eastern Slav civil war, a synthetic Plaga species was engineered based on Type 2 and the dominant species by the government's researchers to emit a sound peculiar to the Licker, bringing them under the control of those carrying the Plaga. During the same conflict, the new Plaga created a weakened type of Ganado who began infecting loyalist soldiers, secessionist rebels and civilians indiscriminately.


Las Plagas is a species of parasite which alters its host's behavior by attaching itself to the central nervous system. The parasite is found between the lungs and beneath the heart, where it can tap into the host's spinal cord. Unlike other parasites, Las Plagas is a social organism, meaning that they live together in social harmony and communicate with each other, even if the hosts belong to separate species. Luis Sera postulates that they have a collective intelligence akin to a hivemind, possibly communicating via ultra-high frequency sound waves. Even when unhatched, the Plagas demonstrate some physical symptoms in the host, like turning the eyes red briefly.[notes 1]

As a Plaga grows inside a host, the host can suffer from some symptoms, in addition to the influence of the parasite on the host's behavior. These include, but are likely not limited to: coughing up blood, blood flowing from the eyes, convulsions, sudden unconsciousness, hallucinations, swelling and discoloration of blood vessels, and discoloration of the iris – usually to a reddish color. The eyes of an infected person can be seen to glow in dark conditions.

The parasites also have a high adaptability rate, as they can possess other organisms than humans. For example, Ramon Salazar uses Plaga-infected wolves as guard dogs in his castle. In addition to the Ganado, Saddler and his men also created several kinds of mutant creatures such as the El Gigante, the Regeneradores/Iron Maidens, Novistadores, Del Lago, the U-3, and Salazar's bodyguards, the Verdugos, as a result of genetic experimentation with the parasites and various other specimens.

All of the members of Los Iluminados, including Saddler himself, have Plaga parasites implanted into their bodies, although the ones used by him and his top underlings (Bitores Mendez, Jack Krauser, and Salazar) are superior to the regular Plaga, allowing their host's complete independence. Additionally, certain feats by individuals infected with Dominant Species Plaga (for example, Mendez lifting Leon into the air with one hand and Krauser mutating his arm into a bladed wing) suggest that these particular Plagas can increase their hosts' physical capabilities.

Regular Plagas have no true mutagenic effect on their hosts' body other than the distinctive red irises, although the parasites may expose themselves if sufficient trauma is inflicted on the host. However, this will only occur at nighttime or in other dark areas, since the Plaga is extremely sensitive to light (a flash grenade will kill a regular Plaga instantly). It is the fact that hosts of regular Plagas exhibit no outward sign of abnormality (beyond discolored irises) that make them such a dangerous threat, as they are much more subtle and invasive than Umbrella's myriad viruses. The Plaga parasite does not stop their hosts from feeling pain, however, unlike the t-Virus zombies, since the hosts have still retained their nervous system, although they do give their hosts better resilience against bullet wounds. Hosts of subordinate Plagas are also capable of carrying out day-to-day routines like ordinary people, despite their frequently bizarre, violent behavior and noticeable deterioration in hygiene.

Also of note, according to a note written by Saddler, the subject's mindset does seem to be important when choosing a host ("the Plaga reflects the conscience of the hosts") suggesting that a Plaga's control over the host can be resisted, even overcome entirely. This seems to be a reference to Sera, who was a host himself before managing to remove his Plaga. This might also explain the need to kill those who refused the Plaga, as they were obviously judged to be "incompatible". It also seems to be a literal description as well, at least in the case of the Dominant Species Plaga, as Krauser, who preferred close combat, developed a bladed arm to suit his needs. In extremely rare cases, the Dominant Species Plaga will also create a far larger body while the host itself is connected to a cocoon-like membrane. This is especially apparent with Ramon Salazar and Ricardo Irving's transformations (although the former was due to fusing with his remaining Verdugo guard and the Queen Plaga instead of using his own Plaga directly) and to a lesser extent Osmund Saddler's transformation.

Another side effect viewed in those infested with Plaga is an apparent biological instability, as seen in that they disintegrate into a black or yellow goo when killed. This is common with nearly all Plaga infested individuals, including both Majini and Ganado. However, certain individuals, such as the first group of Ganado that Leon encountered in Resident Evil 4 and minibosses, do not disintegrate when killed. The Plaga themselves, for the most part, also suffer the same fate upon death. However, there are some cases of the Plaga itself remaining intact after death.[notes 2]

In the game, the Plaga of the Ganado, Cultists, and Combatants only appear where the head is. Once a Plaga is exposed, the enemy will no longer sprint towards the victim.

The Majini located within Kijuju are infected with a different type of Plaga, created through extensive research. The Majini have been shown to develop strange mutations, such as tentacles within their mouths, as well as the ability to fully open their mouth/jaw to expose tendrils to attack others. It has also been shown that the Plaga within Kijuju appears to be completely awakened already, and enter via the mouth or throat, already hatched. They seem to grow inside the host of another Plaga, which will later transfer them to other possible hosts, eliminating the need to inject the egg. This Plaga also does not appear to be harmed by sunlight, as they appear within brightly lit areas. Some strains have also been shown to fly after leaving the host body. Despite these new modifications, they are still vulnerable to the bright flashes of flash grenades (i.e., UV light).

Plaga SpeciesEdit

Subordinate Species Plaga - These are the common Plaga species. They have no individual form by nature, and it is not certain what dictates their manifestations.

Dominant Species Plaga - These are the complex types of Plaga which were genetically modified for the host to retain control. They have three distinct abilities which separate them from Subordinate Plaga - they allow the host to retain their free will, control other Plaga, and cause dramatic mutations in their host at will. They are the opposite of the Subordinate Plaga and allow the host to exert complete control over the parasite. The only known subjects to have ever been infected with this Plaga were Osmund Saddler, Bitores Mendez, Jack Krauser, Ramon Salazar, Ricardo Irving, and Alexander Kozachenko. Notably, this type of Plaga can create compelling individuals, while having almost no detrimental effect on the host's mental capacity; something Umbrella's top virologists failed to manufacture.

Plaga Life CycleEdit

Resident Evil 4 - Las Plagas 1

Plaga A parasite replacing the head of its host

Once it hatches inside a human host, the larval Plaga undergoes three primary stages of development.
  • Plaga A[2] - This is the first form of Plaga that Leon will encounter. Their bodies are pulsating masses of flesh and waving tentacles, with the longest tentacle-armed with a scythe-like blade that can slash at the player from a decent range, and also while they are knocked on the ground. They are the weakest of the Plaga species and can be killed with minimal effort. Type A Plaga is commonly found in Villagers and Militia and also control the weaker Armadura suits.

Plaga B, erupting from a zealot's head.

Plaga Infection

Plaga C

  • Plaga B [2] - These Plaga are the second form of Plaga that Leon will encounter infesting human hosts. They are often found inside the lower-ranking zealots and are the second type which controls Armaduras. This version of the Plaga can extend its entire body (being the Plaga itself) towards Leon, and it will devour his head—an instant kill. The B-parasite is capable of no other attacks. It is at a high risk that you should ever get close to this Plaga due to its one-hit kill effect. While not advisable, it can be killed with a knife. Interestingly, this type of Plaga does not destroy the host's head or body when revealing itself. As with the type A Plagas, it can be killed using a flash grenade.
  • Plaga C - These Plagas mostly inhabit the higher ranking zealots and militia. They are the most durable, can spit acid from some distance, and detach themselves from their host following death. They are roughly equal to the A-parasites regarding threat while attached, and are relatively weak when detached. While detached, they have a leaping grapple which lacks an animation for attacking from the side or rear, much like the Colmillos, meaning they can only use it when directly in front of Leon. Curiously, several are encountered in the game without hosts at all, such as in the case of the battle with Salazar. When without a host, a C-parasite will eventually die, even if it has taken no damage from the player. As they can't climb ladders, simply moving outside their immediate area is an effective way to kill them.


The Plaga are very vulnerable to bright light. They will only emerge from their hosts at night (except in The Mercenaries), and can be instantly killed by throwing a Flash Grenade at them (except for Plaga Cs that are attached to a host; with these, a flash grenade will dislodge them from their host, while it takes a second to kill them).

A weapon called the Plaga Removal Laser 412 (P.R.L. 412), which is unlockable after completion of the Professional difficulty, can instantly kill any enemy infected with Plaga. It is presumably a weaponized version of Luis's machine.

The kind of radiation the Plagas are weak to seems to be UV light, since most lights used to destroy it are colored blue/purple, meaning that they emit enough UV light. Another possible explanation for their photosensitivity is that they may react to a certain level of Candela (meaning that the brighter something is, the stronger it is against the Plagas).

Known treatment Edit

Only a dormant Plaga can be treated, as type 2 and type 3 infect the host too fast. Therefore, making treatment with these type of Plaga impossible without killing the host.

Suppressor Edit

If a person has become the host of the parasite, the parasite's growth can be suppressed by taking medication. These special pills are produced by Luis Sera, a researcher who betrayed Saddler.

Radiation Treatment Edit

However, once the Plaga has hatched, then the only way to terminate the parasite without killing the host is for them to undergo a special kind of radiation treatment.[3] This painful procedure has the possibility of impairing the host's consciousness, and may still kill the host if the Plaga has already matured into adulthood.

Luis Sera also designed a machine which produced this kind of radiation after extensive research regarding how the Plagas might be removed. Ironically, he was tasked with finding a way to prevent any form of removal of the parasite by Saddler. Leon and Ashley, who had Plagas implanted into their bodies, used the machine to eliminate the Plagas, with both managings to survive the operation, as the Plagas had not reached their adult stage.

Direct Damage Edit

Although killing a Plaga once it has bonded with a human's central nervous system is likely to result in the death of the carrier, it is possible to kill the Plaga once it has bonded with a human's spine without killing the host. However, it will result in the individual being permanently paralyzed from the waist down for the rest of their life. This was especially notably seen in the Eastern Slav resistance member, Buddy.

Further notesEdit

  • All lower level Ganado are shown to have lost their need for personal hygiene, due to the observations Leon makes in the first few chapters of the game and various water sources throughout the game.
  • The B-Plaga is the only of its kind (human host Plaga) that can perform an instant death attack, by literally biting Leon's (or any other of the Mercenaries in the mini-game) head off. This Plaga can also kill Ashley, having the same "head eating" animation, but would just hit her, making her fall lifeless in the floor.
  • In Resident Evil: Damnation the new Plaga strain emits a sound which the Licker can hear; that allows it to be controlled by anyone who is infected with a Master Plaga sample.
  • The English localization of Resident Evil: Umbrella Corps inaccurately refers to the ordinary Plagas of Spain as "Dummy Plagas." They are referred to instead as "recessive" in the Japanese game.

See alsoEdit


  1. When Mendez ambushes Leon in the hallway of his house, Leon's irises when struggling against Mendez's strangulation of him briefly turned red, which led to Mendez deducing that Leon "carried the same blood" as the Los Illumnados. This occurred before the eggs hatched.
  2. Albert Wesker managed to retrieve an intact version of the Dominant Species Plaga via recovering and autopsying Krauser's corpse, and supply it to TRICELL for mass-production.
  1. Resident Evil 4 Digital Archives, P65, Final Designs.
  2. 2.0 2.1 Biohazard 4 Kaitaishinsho Katei Ban, page 92
  3. Resident Evil 4 (2005), file: "Luis' Memo 5"