The Transhumans were created by combining human DNA with DNA from a specific kind of animal so they would be better equipped to withstand harsh environments. They were designed by Manticore in the early 1990's.
Desert transhumans are designed to operate in extremely dry environments. They have a high heat resistance and possess an enhanced ability to conserve body water. These units have extensive training in desert combat tactics and survival techniques. They tend to have a scaly, lizard-like appearance.
Polar transhumans are designed to operate in extremely cold environments. They have an increased ability to conserve and produce body heat. They have extensive training in cold-weather combat and survival techniques. They tend to have white hair and a very pale appearance that helps them blend into the snowy environment.
Maritime transhumans are designed to operate in various underwater environments. They have a genetically modified gill-like breathing structure that allows them to survive in both saltwater and freshwater. This structure, while advantageous in a water environment, does not allow for breathing of atmospheric air, requiring the soldier to wear an enclosed water-breathing apparatus while operating outside of the water. While outwardly human with the exception of their gills, they are not capable of human speech, instead communicating in "clicks" like dolphins. They reproduce by laying eggs, with a single couple producing several. These units have extensive training in maritime warfare, including underwater combat tactics, explosives and sabotage.