Donald Anderson, also known as Mr. Sigint or simply Sigint, was a former member of FOX and an expert on weapons, equipment and cutting-edge technology. He assisted Naked Snake during Operation Snake Eater and the San Hieronymo Incident, participated in the development of ARPANET, and was one of the founding members of Cipher. Anderson later became the chief of DARPA, supporting the development of Metal Gear REX in the early 2000s. During the Shadow Moses Incident, he was tortured to death by Revolver Ocelot of FOXHOUND, and later impersonated by Decoy Octopus.