The Grays were humans that collaborate with Skynet by helping make T-888 Terminators more human-like. Four were captured and tried as war criminals by the Resistance; however, the fifth named Fischer eluded capture and was sent back to 2007.
The primary purpose of the Grays was to teach Skynet's forces, namely Terminators, human behavior such as how to interact with, and torture humans.
According to Jesse, Derek Reese (in Jesse's timeline) was one of the test subjects tortured by the Grays, specifically Charles Fischer. However, Derek has no memory of this and suspects that he or the Connors altered time in such a way that the event she remembers never happened in the timeline he is from.
Fischer's mission in 2007 is apparently to insure the ability of Skynet to seize the computer network infrastructures, by utilizing his past-self's access to the SRF facility and his future-self's knowledge of advanced programming techniques to install permanent back doors into numerous government and Defense Department networks.
Behind the scences
- The Grays could be a references to the supposed aliens "Greys", known to abduct and torture humans. Betty and Barney Hill, and Travis Walton are among the thousands who claim to have been abducted and subjected to horrifying medical procedures.
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