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This article, Chimera Parasite, is a stub and may require expansion. Please help out by editing the page.

The Chimera Parasite, also known simply as the Parasite or the Bacteria, is an alien organism that has arrived on Earth. Humans infected by the organism are known as Roaches. Years after its arrival, the organism has evolved to not require a host, spawning the Archæans.

The Parasite appears as enemies in the Outbreak and Containment events of Tom Clancy's Rainbow Six Siege as well as Tom Clancy's Rainbow Six Extraction.


The origins of the Chimera parasite are unknown. At an unspecified point, it arrived on Earth and was found by the Soviet Union. For unknown reasons, the Soviets stored the Parasite aboard a capsule and sent it out into space. The capsule returned to Earth in early February 2018 and crashed near Truth or Consequences, New Mexico. The capsule containing the parasite was subsequently found by Boyd Brooks. Brooks loaded it onto his truck and brought it back to his garage in his salvage yard. He then sought to sell it by posting it online but unknowingly became the first to be infected by the parasite. Over the next ten days, the parasite infected the majority of the town's population though government officials were able to successfully contain it for the time being. It was at this time that those infected by the parasite began to be known as "Roaches". Rainbow was later ordered to enter the town to help prevent the government from using a nuclear weapon to stop the parasite. While Rainbow was unable to stop the town's destruction, they were able to rescue Dr. Ellen Mackintosh who had been working on a possible cure after taking blood samples from Boyd.

Over the next few years, the parasite had evolved into the Archæans and had spread to other areas in the United States, notably New York City, San Francisco, and Alaska. New containment zones were subsequently establish around afflicted areas. To combat the Archæans, Rainbow established REACT and conducted various mission within these zones to gather more information about the parasite to discover a way to stop it.


Human infected by the Parasite mutate into the Roaches. Five different variants of them have been observed:


Archæans, nicknamed Archies by REACT Operators, are an evolved form of the Parasite that no longer require human hosts. Thirteen different variants have been observed:

Parasite Biomass[]

Areas infected by the Parasite have been shown to be covered with several biomass structures: