Eli

Eli was a mysterious boy Big Boss encountered while on a mission to rescue Kazuhira Miller from Afghanistan.

Behind the scenes
Eli made his debut appearance in the E3 2013 trailer for Metal Gear Solid V: The Phantom Pain. In the trailer, he is described as "A Youth who Curses his Fate."

In an interview with Game Informer during the leadup to Ground Zeroes, Yoji Shinkawa, when inquired about the identity of Eli (namely, whether he was Liquid Snake) said he was forbidden to answer at the moment.

A theory for Eli being Liquid Snake is the link between Les Enfants Terribles and certain biblical figures. In the old testament, Jesse, the son of Obed had eight sons, one of these being name David (who later became the second king of the United Kingdom of Israel) and the other being named Eliab (which poses supicious links to the name Eli). The link beween Les Enfants Terribles is that originally there were eight eggs, six of those eggs were aborted leaving just Solid and Liquid to be fertilized. With Solid Snakes real name being David and (by this theory) Liquid Snakes real name being Eli it is a perfect match.