Sarin was a Suliban female and former member of the Cabal. During her time in the Cabal, she received a number of genetic enhancements, including the ability to shapeshift and to measure the trustworthiness of an individual provided she was in close physical proximity to them.
Sarin eventually became disenchanted with the Cabal's activities, and formed a resistance movement with several other Cabal members. In this capacity, she met with the Klingon courier Klaang on Rigel X, and provided him with proof that the Cabal was staging attacks within the Klingon Empire in an attempt to start a civil war in 2151. Later, Sarin and her compatriots encountered Starfleet Captain Jonathan Archer who, along with other members of his crew, had traveled to Rigel during an investigation into the whereabouts of Klaang, who had been kidnapped by the Cabal. Sarin had Archer's crew detained while she attempted to determine Archer's true intentions. Upon coming to believe that Archer was telling the truth about wanting to return Klaang to Qo'noS, Sarin released Archer's crew and offered her assistance in the completion of their mission. Sarin was murdered by Silik, however, when the group came into conflict with the Cabal. (ENT: "Broken Bow")
Later that year, Archer, upon learning more about the Temporal Cold War from the Temporal Agent Daniels, related to Commander Charles Tucker III and Sub-Commander T'Pol that Sarin had used the exact same term to describe the conflict, and that what she had told him seemed to align to the information relayed by Daniels, although T'Pol remained skeptical. (ENT: "Cold Front")
While Captain Archer was enduring imprisonment in Tandaran Detention Complex 26, Colonel Grat questioned him about Sarin, reminding Archer that she had been "the head of a Suliban resistance cell," that he had contacted her, and that she had died during the firefight on Rigel X. (ENT: "Detained")