Dr. Hal "Otacon" Emmerich was the chief engineer of Metal Gear REX. He became a close friend of Solid Snake after Snake rescued him during the Shadow Moses Incident in 2005. Later that year, he and Snake founded the anti-Metal Gear NGO Philanthropy. Following the Guns of the Patriots Incident, he became the adoptive father of Sunny. A devoted fan of anime, Hal's chosen nickname was derived from the Japanese animation convention Otakon.