Another former member of Snake's support crew from Snake Eater. He assists Snake in the game while working for ARPA.
After successfully contacting Para-Medic during the San Hieronymo Takeover via a Red Army communications base, Para-Medic patched Snake's call into Sigint from his command station at ARPAnet. Sigint informed Snake that Major Zero and Snake were both being held under suspicion of treason, and that if he wasn't able to produce documentation proving his innocence, not only would he and Zero he imprisoned, but Sigint and Para-Medic would also be court marshalled and placed under arrests as accomplices to treason. Sigint then tells Snake that he does have some help this time around, as ARPAnet had recently sent a Green Berets squadron to the peninsula, however they had lost contact with them shortly after their arrival. Unbeknownst to Sigint, Snake had already met and befriended the only survivor of the Green Berets squad, Roy Campbell. Sigint also suggested to Snake that he recruit some allies for his cause, given the low morale of some of the Red Army.
After being recruited by Zero to become one of the founding members of The Patriots, he used ARPAnet, the precursor to the Internet, to plan their later virtual control over the world. DARPA was also in charge of much of The Patriots developmental plans, most likely including the central AI, JD, as well as GW and the other surrounding AI.
