Carbon Human is a type of genetically-modified human besides Coordinators and Naturals that appear in Cosmic Era. They were created from data on individuals possessed by Librarian Works, these are specific people who can be recreated limitlessly. Like a "carbon copy", these are "similar but differing replications," and so are called "Carbon Humans." They are not clones, but are created from the implanting of specific DNA and memories into another human body. Depending on the DNA used, this technology produces a result similar to Coordinators. Using this technology, it is also possible to resurrect someone who has already died. However, how much the Carbon Human resembles the original person is something which depends on the data on the individual which Librarian possesses, and Carbon Humans cannot be created from people on whom there is insufficient information. The Librarian organization created numerous Carbon Humans of skilled mobile suit pilots to increase their fighting force.
To create Carbon Humans, Librarian Works uses samples of data (such as genetic code) based on the subject to create new cells for the host body. Using a retrovirus, new genetic material is injected into specific cells, replacing the old cells. As part of the metabolic process, these old cells are replaced by new cells every ninety days. Carbon Humans can be implanted with memories of the original person if needed. Hormonal readjustments and the altering of chemicals to control their brain activity are also applied. In order to the match the original subject's persona, the body used must have the identical biological age recorded in the original's data. Without the required data, a new unique personality will develop. The process is carried out inside a special tank, in which the Carbon human is immobile, over a period of six months.
Even though Carbon humans are based to a large degree on the original subject's genetic template, they can develop characteristics and identities distinct from the original due to genetic differences. Despite having implanted memories, A Carbon human does not suffer from an identity crisis, and know they are a separate individual from the original. This also helps the Carbon human avoid various psychological impediments. With this method, Carbon humans of originals of various ages can be created.
It is unknown when the first Carbon Human were created but they were already appear before the Second Bloody Valentine War ended through the affiliation with the Librarian Works. They make their first appearance in the Third Bloody Valentine War.