Unlike Umbrella’s viruses, Las Plagas were not born in a lab. They are an ancient parasite that controls whoever carries it, and a religious cult kept and worshipped it in a rural part of Spain. In 2004 that cult tried to use it against the President of the United States, and what was left of it ended up with Wesker and Tricell. This page follows the parasite from start to finish: the Salazar castle, Resident Evil 4 chapter by chapter, Ada Wong’s side of it, the samples that left the island and their arrival in Africa in Resident Evil 5.
For the wider picture of the period, see The bioterrorism era; Wesker’s story has its own page, and the dates sit in the timeline.
A parasite sealed under a castle
Spoilers: Resident Evil 4’s backstory.
The region where Resident Evil 4 takes place has no name in the game. Later material calls it Valdelobos, and so does the saga’s wiki. Centuries ago it gave birth to Los Iluminados, a cult that worshipped Las Plagas, a parasite able to get into a human body and rule it.
The cult’s history comes in two versions, and neither is settled. In one, Los Iluminados were persecuted from the late 15th century. In the other, they were a heretical sect: an inscription by their prophet Adam Saddler dates it to 1554, and it was crushed in 1741 under the prophet Hester Saddler. Both versions end the same way. The region’s first castellan, Gregorio Salazar, 1st Count of Valdelobos, locked the surviving Plagas in caverns and built a castle on top.
For centuries the Salazars watched over that seal. Ramón Salazar’s official profile puts it in one line: the previous castellans tried to suppress the religion. In the castle, the Castellan Memo has Ramón tell it himself: the first castellan stripped the cult of its rights, and he, the 8th castellan and a believer in Los Iluminados, wanted to atone for that sin.
Two pieces of that world are worth keeping in mind, because they come back later:
- Los Iluminados are not a company or an army. They are a faith, and their believers are the hooded Zealots who fill the castle.
- The Plaga is not a virus. It is an organism that grows inside its host. When you blow an infected person’s head off, the parasite can burst out of the neck and keep fighting.
Saddler and the cult’s return
Spoilers: Resident Evil 4’s backstory.
The cult comes back with Osmund Saddler. He arrives in the region as a healer, in the 1990s or the early 2000s: the wiki’s pages disagree on the date. There he finds an isolated, easily swayed young man, Ramón Salazar, the 8th castellan, who claims to be twenty. Saddler makes him feel guilty for his ancestors’ “sin”, and Ramón breaks the seal his family had kept for centuries.
The Plagas in the caverns were mummified, but their spores were still alive. Over the years they regenerated inside the miners who worked there. Saddler then converted the village chief, Bitores Mendez, and through him the whole village. The villagers were injected with the parasite in a “cleansing ritual”. That is where the Ganados who greet Leon with pitchforks and axes come from.
The third name in this story is Luis Sera. He was born in the region, studied biology and, per the wiki, was 28 in 2004. Around 2000 Saddler hired him to lead the Plaga research on the cult’s island. Luis engineered the Dominant Plaga, a strain that lets its carrier give orders to the others. It is the piece everyone will want to steal.
The cult ended up in three tiers:
- Saddler, the leader, who commands every infected person.
- Salazar, the castellan, who keeps the Queen Plaga in his tower.
- Mendez, the village chief, who controls the villagers.
The plan: the President’s daughter
Spoilers: Resident Evil 4.
Saddler did not want a village. He wanted the United States. His main plan was to infect the President’s daughter and send her home: a “Manchurian candidate” who would infect the people around her father. If that failed, he had a plan B, a paramilitary force and a warship.
You can read it in his own words in Our Plan, the file on the island’s altar in 5-3.
Three players after one sample
Spoilers: Resident Evil 4 and Separate Ways.
Saddler’s plan leaked from the inside. Luis, full of remorse, wrote to a university friend for help. That friend was dead, and the person who read the email was Ada Wong, who worked for Umbrella’s rival company. The saga calls it “the Organization”; some wiki pages identify it with H.C.F.
Albert Wesker worked with that company, though he was already meeting Tricell in secret. First he sent his own man: Jack Krauser, a former US Army major and Leon’s partner in Operation Javier (2002). Krauser had faked his death that same year to join Wesker; sources disagree on whether it was a plane crash or a car crash. His job was to infiltrate the cult and steal a Dominant Plaga. The Organization did not trust Wesker and pushed him to send Ada as well.
To win Saddler’s trust, Krauser kidnapped Ashley Graham, the President’s daughter, on her way home from her college in Massachusetts. He used a fake Secret Service detail and shipped her to Spain in a container. It happened in autumn 2004, though one wiki page says August. The Info on Ashley file is the first thing in your inventory.
Meanwhile Luis fled the island with a Dominant Plaga egg to hand to Ada. Mendez’s people caught him in the village. That is where the game starts.
Resident Evil 4: the village
Spoilers: Resident Evil 4, chapters 1-1 to 2-3.
Leon S. Kennedy, a Raccoon City survivor and now a government agent, reaches the village six years after that night, aged 27. Two Spanish police officers come with him.
- 1-1. The villagers burn one of the officers on a pyre, and a truck pushes the patrol car off the cliff. Leon holds out in the plaza siege until the church bell rings and everyone leaves to pray. The one who rings that bell is Ada, though only Separate Ways tells you so. At the end, Leon finds Luis locked in a wardrobe, and Mendez knocks them both out.
- 1-2. Leon wakes up tied back to back with Luis. They escape, and Luis goes his own way. While Leon was unconscious he was injected with a Plaga, though he does not know it yet. At the chief’s house, Mendez grabs him by the throat, senses the parasite (“the same blood as us”) and lets him go. The Chief’s Note is in that house.
- 1-3. If you go back into the bedroom at the start of the chapter, an optional scene shows Mendez attacking you again and a woman in red shooting him through the window. The chapter ends on the lake with Del Lago. Afterwards Leon coughs up blood and passes out for six hours.
- 2-1. Leon wakes up at night with an Anonymous Letter from Ada beside him. He sees a Plaga burst out of a Ganado for the first time and faces El Gigante, which carries one on its back too. With the Round Insignia he gets into the church and finds Ashley. Then Osmund Saddler appears and tells them both that they carry his Plaga.
- 2-2. Leon and Ashley escape through a window and cross the village to the cabin where Luis is waiting. The three of them hold off the siege. Luis then leaves to fetch “something he left behind”, the sample, and Ada meets him on the way. The Sera and the 3rd Party file makes it clear the cult already knows someone else is in the game. That night Hunnigan reports that the rescue helicopter has been shot down.
- 2-3. Leon kills Mendez in the slaughterhouse. His False Eye opens the retinal scanner at the exit, and the road leads to the castle.
Resident Evil 4: the castle
Spoilers: Resident Evil 4, chapters 3-1 to 4-4.
- 3-1. Leon and Ashley blast the castle gate open with a cannon. Inside, Ramón Salazar introduces himself, surrounded by Zealots, the faithful of Los Iluminados. In a courtyard, Luis crosses their path: he says he has lost something and leaves. The Capture Luis Sera file shows the cult is hunting him. At the end of the chapter a trap takes Ashley away.
- 3-2. Salazar breaks into Leon’s radio to taunt him. Per the wiki, Krauser had given him the frequency. The Novistadors appear in the sewers. In the Hall of Rites a group of Zealots hold a ritual. You read Luis’ Memo. At the end, Ada shows herself for the first time and Leon works out who she works for: Wesker.
- 3-3. After the cage with the Garrador, the chapter ends in the Instruction Hall with Luis’s death. Saddler runs him through and takes the Dominant Plaga. Before dying, Luis gives Leon pills that hold back the parasite. According to Separate Ways, Ada sees it all and tells Wesker. The Female Intruder file is about her.
- 3-4. Leon frees Ashley, pinned to the wall of the hall where Luis died. She escapes on her own and you play her through the servants’ quarters, unarmed.
- 4-1. Together again, they cross the heart of the castle. In the ballroom Ashley is taken once more. The Sample Retrieved file confirms the cult already has what Luis stole, and Ritual Preparation announces what comes next. The Verdugo waits in the basement.
- 4-2 and 4-3. Leon goes down into the mines and up into some ruins. There the Letter from Ada is waiting: Ashley is running out of time before the Plaga takes over.
- 4-4. In the tower, Salazar tells Leon his plan, and Leon drives a knife through his hand. Salazar sends Ashley to Saddler’s island and then fuses with his bodyguard and the Queen Plaga into a single monster, Ramón Salazar. After beating it, Leon goes down to the docks, where Ada is waiting with a boat.
Resident Evil 4: the island
Spoilers: Resident Evil 4, chapters 5-1 to final.
The island is a military base turned into a lab. Its infected are no longer peasants or monks but soldiers. Luis worked here, and the Regenerators are waiting.
- 5-1. Leon arrives in Ada’s boat, and Saddler calls him on the radio the moment he sets foot on land. Luis’ Memo 3 is in the main operating room. Leon finds Ashley locked in a cell.
- 5-2. A Paper Airplane from Ada flies in through the window and shows them the way out. At the end of the chapter Saddler takes control of Leon’s Plaga and carries Ashley off, and Leon manages to plant a tracker on him.
- 5-3. Our Plan lies on the altar. Ada and Krauser talk about Saddler and the sample. Then Krauser faces Leon in a knife duel and admits he took Ashley “for Umbrella’s sake”, to win Saddler over and get the sample. After U-3, Leon beats the mutated Krauser in the ruins but does not kill him. Krauser’s Note and Luis’ Memo 4 belong to this chapter.
- 5-4. Saddler calls to say Krauser was only a distraction (Communication Log: Saddler #3). Mike covers Leon from his helicopter until he is shot down. Ada finds Leon, and his Plaga tries to turn him against her. Leon rescues Ashley, and Luis’s machine removes both their Plagas. Luis’ Memo 5 explains how it works: a special radiation kills the Plaga, very painfully, and can kill the host too if the parasite is already an adult.
- final. Leon reads Our Mission and rides up to the construction site, where Ada hangs from a rope. Saddler mutates. Ada throws Leon a special rocket launcher and Saddler dies. Then Ada takes the sample at gunpoint, leaves by helicopter, sets off the bomb that will blow up the island and throws Leon the Jet-ski Key. Leon and Ashley escape on the jet ski.
The United States gets the President’s daughter back, and Los Iluminados lose all three leaders in one night. But the Dominant Plaga leaves the island in Ada’s bag.
Ada’s side: Separate Ways and Assignment Ada
Spoilers: Separate Ways and Assignment Ada.
Separate Ways tells the same days from Ada’s side, in five chapters you’ll find under Extras:
- Ring the bell: Ada is the one who saves Leon in the plaza in 1-1.
- Rescue Luis Sera: Luis has been drugged and is about to be sacrificed. On the way Ada runs into a Dr. Salvador, a Bella Sister and a Gigante.
- Retrieve the sample: Wesker orders her to kill Leon if she meets him. She lies and says she had no chance. It ends when Saddler kills Luis.
- Stop Leon’s assassination: after talking with Krauser at the radio tower, Ada sinks Saddler’s warship, his plan B, and saves Leon from Krauser’s knife.
- Obtain the sample: Ada kills Krauser, Saddler captures her, and she gets hold of the special rocket launcher she ends up throwing to Leon.
In Ada’s closing report, the Organization wants the sample. She had been ordered only to pretend to serve Wesker, and she sends him a different sample. “The battle is just beginning.” The wiki treats Separate Ways as canon.
Assignment Ada is not: the wiki marks it as non-canon. In that minigame Ada collects five Plaga samples on the island for Wesker and reports that Krauser is dead. Wesker speaks of “significant changes in our world”.
Where the samples went
Spoilers: Resident Evil 4 and Resident Evil 5.
The wiki’s pages on the Plaga, Ada, Krauser and Wesker tell the same story:
- Ada kept the Dominant Plaga for her employers and gave Wesker a Subordinate Plaga, the less valuable kind.
- Wesker did not settle for it. Krauser had implanted the sample in himself, and Wesker recovered a Dominant Plaga from his corpse.
Those Plagas ended up with Tricell, the company Wesker was already dealing with in secret. The pharmaceutical company, through its Africa director Excella Gionne and its middleman Ricardo Irving, turned the castle’s parasite into a product. Tricell Researcher Miguel’s Journal - No. 1 says it plainly: Tricell already had samples of the t-Virus, the G-Virus, T-Veronica and Las Plagas.
Kijuju: Las Plagas reach Africa
Spoilers: Resident Evil 5.
In March 2009, Chris Redfield and Sheva Alomar arrive in Kijuju, West Africa, to catch Irving before a bioweapons sale. The BSAA’s operation is told in The bioterrorism era. Here, what the parasite does is enough.
Kijuju’s infected are the Majini, a local word for “evil spirit”. The Majini file goes over the story from Salazar’s castle and Kennedy’s report. Tricell worked with two new strains:
- Type 2. An adult Plaga forced in through the mouth that controls its host in about ten seconds. The Resident Evil 4 strain took hours or days. It does not need a control Plaga either, and carriers infect others. The Type 2 Plagas report describes three field tests in Kijuju itself: infection, control to attack the BSAA, and combat. The whole town is a trial, and the Town Majini are the result.
- Type 3. A base Plaga with a control Plaga gene. Irving gave it to the Ndipaya tribe, passing it off as a vaccine. Per the Type 3 Plagas Field Test, it takes in 92% of adult and teenage men and in no women or children. Carriers jump higher, and some grow to nearly three metres: the Giant Majini. The Village Youth’s Diary tells the “vaccine” from the inside, with children dying of fever and men turning violent. That is where the Wetlands Majini of 3-1 come from.
Irving’s note adds a weakness you already knew from 2004: Las Plagas cannot stand intense light. That is why a flash grenade kills the exposed ones.
Tricell also used the parasite to build weapons. The U-8 in 5-1 is a Plaga-based B.O.W. that Irving sold, per its file. And Irving himself, cornered on his ship in 3-3, injects a Dominant Plaga, the same strain Luis designed for Saddler. Before he dies he points to the caves and names Excella. Irving’s file describes him as the foreman of Tricell Africa’s refinery and a black-market B.O.W. dealer.
One detail closes the circle, though only as a hypothesis. The wiki notes that some remains in the Ndipaya ruins suggest Las Plagas may have originated in West Africa. No game confirms it.
Kijuju does not end with Las Plagas but with Uroboros and Wesker’s death in a volcano. That part is on Wesker’s page.
After Kijuju: Las Plagas in the films
Spoilers: the CG films Damnation and Vendetta.
The CG films are part of the games’ continuity, and the parasite keeps turning up in them. They are covered in Films and series:
- Damnation (set in 2011). In the Eastern Slav Republic’s civil war, the government secretly hands the rebels a defective Type 4 Plaga. A Dominant Plaga carrier can command Licker βs. Ada, posing as a BSAA agent, steals a sample. Per the wiki, Derek Simmons had hired her anonymously.
- Vendetta (set in 2014). Surviving members of Los Iluminados supply Plagas to the arms dealer Glenn Arias to build the A-virus. Their mole, Patricio, helps The Family blow up Leon’s DSO team.
The wiki adds that after 2004 the Spanish government quarantined the region. The cult never again had the power it had that night, but its Plagas stayed on the market.
Where to go next
- The BSAA’s operation in Kijuju, the agencies and the C-Virus crisis: The bioterrorism era.
- Wesker, Uroboros and his end: Albert Wesker.
- Every date in order: the timeline.