FOX Unit support member. An expert in weapons and equipment as well as the latest technology, he communicated with Naked Snake via radio.
Major Zero's decision to hire Sigint, a black man, during the 1960s amid pervasive racism in the CIA earned him a reputation of being a maverick. The codename Sigint came from the common abbreviation of Signal Intelligence, the area of intelligence that deals in using transmitting devices to collect data. He was responsible for inventing much of Naked Snake's equipment, including his binoculars and the Raikov mask, and had a surprising accurate picture of where technology would lead in the future.
Real name Donald Anderson. After Operation Snake Eater, he joined ARPA and began research on networks that would lead to the basis for the Internet. He joined Zero's Patriots, and later became chief of DARPA, working at Shadow Moses Island on the development of Metal Gear REX. He became a hostage when Liquid Snake took over the facility, and was ultimately killed under the guise of torture at the hands of Revolver Ocelot.