Olga's Child

Olga's Child is the unnamed child of Olga Gurlukovich, a leader of a mercenary army who died at the hands of Solidus Snake.

Olga gave birth to the child at a hospital run by The Patriots, an organization that secretly runs the United States without the knowledge of its citizens. The Patriots took Olga's child away from her, and, until her death, sent her a photograph of the child at an interval of time (believed to be every few months). If Raiden were to have died during the Big Shell incident, then Olga's child would have been killed as well, by the Patriots.

Metal Gear Solid 4
It is unknown what role, if any, Olga's child will play in Guns of the Patriots, though at the outset of the game, which has been confirmed to be 2015, the child would be about seven or eight years old. Raiden and Solid Snake have both remarked that they will in some way ensure the child's safety. In promotional artwork for the game, Raiden has been seen holding a small child, but it is unknown whether this is Olga's child or Raiden's own.

It should be noted that the Patriots' taking of Olga's child is similar to The Philosophers' taking of The Boss' son, Revolver Ocelot. It is possible that the Patriots may be training Olga's child to become an agent, much like Ocelot.