- "Pariah may be the only thing that can stop Mercer and Greene. They may not let me know what he is, but I can guess... what if Pariah was a perfect realization of all non-encoding regions in the genome? It may be the final purpose of all life on earth."
- ―Dr. Raymond McMullen[src]
Pariah is the son of Elizabeth Greene, who was captured during the outbreak of Hope, Idaho in 1969. He is considered a completely different form of being from Elizabeth Greene and Alex Mercer, and by extension, James Heller, since Elizabeth is an imperfect release of non-coded regions of the genome, while Mercer is an artificial release. Blackwatch scientists speculated that Pariah could be the final purpose of all life on earth.
He was chosen as the prime test subject in Project Crusade and was responsible for five deaths by unknown means during his thirty-four years of captivity. Whether this was due to his sociopathic behavior or infection caused by the virus is unknown. He shows no outward signs of physical deformity and tested negative for all the 14 strains of the virus his mother is infected with.
Alex Mercer and Pariah have been said to have much in common. Alex is an artificial release of uncoded areas of the genome, whereas Pariah is a perfect natural release. As a result, it has been speculated by Blackwatch scientist Raymond McMullen that it would be 'extraordinarily bad' if the two of them ever met face-to-face. McMullen speculated that Pariah was the only being capable of stopping Alex Mercer.
- Some rumors and popular beliefs state that Captain Cross is "Pariah". However, the Supreme Hunter, which is fought at the end of the game, consumed Captain Cross and took his form, discrediting this theory.
- Other rumors say Pariah is the Supreme Hunter himself, and some say that the previous runner killed by Captain Cross was Pariah. However, in the Web of Intrigue node, it is said that all previous Runners have always been female, as was the last one, whereas Pariah is male. Also, the Supreme Hunter was not a Runner at all, but the form the "cure" took after being rejected by Elizabeth Greene.
- A Web of Intrigue node (Anthony Savoie PhD in SEQ 7) suggests that the purpose of the Hope outbreak was to breed the ultimate life-form, and that perhaps Pariah is this life form.
- Pariah's name appeared while Col. Rooks debriefed about Barnes Griffin. Griffin's assignment during the second outbreak was to "Project Codename: Pariah".