Sunny is the daughter of Olga Gurlukovich from Metal Gear Solid 2 and the adopted daughter of Hal Emmerich. Kidnapped by the Patriots as a newborn, Sunny was injected with life-monitoring nanomachines programmed to kill Sunny should an operative fail or die in a mission.
The Patriots used Sunny to manipulate Olga and forced her to help Raiden in the Big Shell Incident.After the Big Shell Incident, Sunny was rescued from the Patriots by Raiden and given under the guidance of Snake and Otacon.
She is a talented computer programmer who, with the help of Naomi Hunter, designed FOXALIVE, the virus which Snake used to disable the Patriots' AIs.