Hal Emmerich/ Otacon/ Age (Shadow Moses 30's) (U.S.S. Discovery 30's) (The Big Shell 30's) (Outer Haven 40's)

The chief engineer and the designer of Metal Gear Rex, the Metal Gear prototype at Shadow Moses. His nickname "Otacon" stands for Otaku Convention, and refers to his devotion to Japanimation.

Otacon originally worked for ArmsTech, but was led to believe that Metal Gear was actually a defensive weapon rather than an offensive one. Upon learning the truth from Solid Snake, he immediately committed himself to ensuring that Rex would be destroyed, realising that he was the third generation of Emmerich men to be involved in nuclear weapons - his grandfather had been part of the Manhattan Project, and his father had been born on the day of the Hiroshima Bomb.

Snake and Otacon became close allies after the events of Shadow Moses. Together, they became part of an anti-Metal Gear organisation called Philanthropy. However, both were framed for the sinking of the tanker in 2007 and forced to go into hiding. Two years later, they came out of hiding when Otacon learned that his stepsister, Emma (whom he always called "E.E.") had been taken prisoner in the Big Shell.

Otacon and Emma had been very close as kids, but after an incident in which Otacon failed to rescue her when she almost drowned with their father in their swimming pool, Otacon blamed himself and ran away from home. He had been having an affair with his stepmother, and their father took his own life when he learned of it. Otacon and Emma cleared things up with each other, but Emma died soon afterwards from stab wounds inflicted by Vamp, a member of Dead Cell. Despite the loss of his sister, Otacon helped Snake and Raiden to complete the mission, and it would appear that they now intend to seek out the Patriots.

5 years after the Manhattan incident. Otacon joins Snake once again to put a end to Liquid Ocelot's PMC army.