Resident Evil’s origins as “zombie games” may have evolved into more variety Steam tags as the franchise has gone on. But zombies have been at the forefront of the lore since its debut. The living undead not reanimated but created, 9 times out of 10 with the intent of bioweaponry.

And whose fault is it?

Umbrella Corp

Umbrella Corp's, now known as "Blue Umbrella", snazzy helicopter in Biohazard.

The Umbrella Corporation, aka the Big Bad Evil Guy of main Resident Evil games, was a multi-industry company that was active in 1980 for a little over two decades. Their evil deeds started with their pharmaceutical division, a coverup for creating viruses and bioweapons.

Driven by their ambition of eugenics, they developed a virus that ran rampant over Racoon City General Hospital. Soon after, it spread across the entire city leading to its eradication. This virus was the T-virus.

T-virus

An infected of the T-virus attacking Leon Kennedy in the 2 Remake.

The T-virus, officially called the Tyrant Virus, was developed by Umbrella Corp as part of their progress to essentially eliminate the need for a military. The start of the Wesker Plan to create a superior race of humans.

What happened to those who contracted the virus was anything but superior. A majority of Raccoon City’s 100,000 population was zombified via contaminated water and attacks. These people weren’t dead and brought back, no they were living and became diseased. The more scientific name given to the zombies was “advanced-stage Cannibal Disease patients”.

To rectify and contain the spread, the government ordered a missile strike that decimated Racoon City.

Lickers + variants

A licker attached to the ceiling of a tunnel with the worst sewer breath in your face.

Those infected with the T-virus are prone to a further mutation into what is known as a Licker. Appearing less humanoid and more creature-like. Zombies who have consumed large amounts of biomass are most likely to become one.

Another conglomerate, Tricell, took advantage of mutation and used already existing Lickers to create a variant species called “Licker β”. This variant was created to be a bioweapon and brought upon the downfall of the town of Kijuju.

A further variant when the President of the Eastern Slav Republic implanted the Licker β with Plaga parasites. This made them possible to be controlled by humans with the aim of taking hold of the nation via a biohazard.

Las Plagas parasite

The model for the las plagas parasite in all its hiddeous glory.

In a remote area of Spain, the US president’s daughter was kidnapped and injected with the Plaga parasite. Resident Evil’s darling Leon Kenndey was dispatched to retrieve her. These parasites were sourced from the Queen Plaga, which was kept in one of Los Iluminados’s towers.

Los Iluminados was a cult devoted to the Plaga parasite. Initially, the parasite was released as a means to atone for the sins of the 8th castellan’s family. The parasite plants spores in new hosts where they eventually take over.

Las Plagas parasites had the ability to form human-animal hybrids, increase human strength, and enhance superior regeneration.  Los Iluminados’ numbers diminished but survived and later their parasitic genes were used to create the A-virus.

A-virus

A huge boss from the 2 Remake, despite the huge bulging eye on its arm, it can't see Claire.

The A-virus, also known as Animality Virus, poses similar symptoms as the original T-virus in infecting humans with the Cannibal Disease. The difference comes with the speed at which the infected lose their cognitive function, giving those with the A-virus more control over their movements.

It also affected their physical abilities in the opposite direction: enhanced speed, strength, and durability. Counter was the high flammability property both the virus and the infected had.

A-virus was concocted by a former CIA agent looking to get into the bioweapon business like his former employer. The virus was spread through contaminated bottled water and the Great Lakes and activated with an airborne trigger.

Afflicted

First look of this kind and the not the last we'll have empathy for these infected.

Another descendant from the T-virus is the t-Phobos virus. During experimentation with fear and human survival, the reaction of the t-Phobos virus infects those already suffering from the T-virus who have been abused and tortured under Wesker.

The mutation’s trigger is fear itself: when the infected becomes scared, they mutate and attack those who are uninfected. Similar to C-virus victims, they do have a higher level of competence and intelligence that normal zombies.

The three variants are given various amounts of more durability.

Mold Pathogen

The mycelium being featured in moonlight right before it's blown to smithereens.

The mycelium Mold was introduced in Resident Evil 7: Biohazard. Utilized by The Connections, they began using its properties to further develop bioweapons. The first being Eveline: a genetic mutation made from the Mold and a DNA sample of a deceased infant named Eva. Those first mutated from the Mold are known as E-type bioweapons.

The currently known E-types are Eveline, Ethan Winters (protagonist of Resi Evil 7 and 8), and three of the members of the Baker family. Similar but still vastly different to the viruses, the Mold becomes one with the infected and the infected becomes Mold. The Baker family became sadistic killers with inhuman mutations.

Biohazard Ending

The Baker Family's home after everything was taken from them. Worse Bed and Breakfast, sorry Marguerite.

The fate of the Baker family was the result of the wreck of the ship Annabelle, which housed Ethan’s wife and Eveline. In the end, Ethan fights and destroys a highly mutated version of Eveline, who when given the cure melted and took over the entire area with Mold.

Doing damage control, Umbrella Corp along with Resident Evil’s hotshot darling Chris Redfield rescued Ethan and his wife. The official cover they leaked to the press was a gas leak under the bayou where Biohazard took place. Said gas leak was what killed the Baker family with Ethan and Mia’s whereabouts unknown.

Their real whereabouts are a safehouse in Europe.

Moroaicǎ & Cadou

One of the Four Lord, Moreau, is his sad depressing glory before he is also blown to smithereens.

The Mold did not originate in Louisiana, instead the fungus supercolony was found by Miranda, mother of Eva after the infant's death in Eastern Europe. After infecting herself, Miranda took up in Romanian town and the Mold manifested in two forms

First is the Cadou; in futile efforts to create a suitable host to bring Eva back to life, Miranda created several Cadou, many of whom died in the process. The Cadou is an organism generated from the Mold and forms itself into a person’s DNA. The main antagonists of the eighth game, Village, are four Cadou that survived; them being the four lords.

The Cadou that originally latches onto the DNA is the host, which can have parts taken from it and used to create more Cadou. In Village, two cases are shown: lord Beneviato and her doll Angie, as well as lord Dimitrescu and her daughters.

Second involves Lady Alcina Dimitrescu. During her tirade to create her daughters, Alcina murdered multiple women from the Northern European town. After infecting them with the Mold upon death, they essentially revived killing pawns for Alcina. Once servants for Alicina and her daughters, the moroaicǎ are now revived husks of their former selves.

Impact on World

One of Umbrella Corp's soldiers on the move to release more deadly viruses for minimum wage probably.

Umbrella Corp’s initial experimentations sparked a mass research craze for bioterrorism. In the main games alone, four conglomerates created their own viruses that sparked destruction in some parts of the world in vain efforts to create superhumans.

While they have done their due diligence of covering up these instances and sending their top agents Leon Kennedy and Chris Redfield to save the day, this is most likely out of their want to make sure the general public doesn’t know of their history.

Blue Umbrella, as it's now known as, has started an epidemic that did not stop with Racoon City. And given the popularity of Resident Evil games and their growing lore, it’s not stopping any time soon.