Solid Snake is the Son of Big Boss. A brother from the "Les Enfant Teribbles" project, along with Liquid Snake and Solidus. He is the main hero of all the games. At the moment he decided to track down the Patriots, while attempting to destroy all Metal Gears for a future for everyone. There is one problem. He had been infected with FOXDIE during the Shadow Moses operation. One day, he will die from this. Only time will tell.....
Grey Fox is Solid Snake's former best friend. He was rescued by Snake at Outer Heaven. However at Zanzibar, Snake defeated Fox in a minefield. Just two soldiers on opposite sides. Fox, in a new prototype exoskeleton, helped Snake out in the Shadow Moses incident. However he was tragically killed by Liquid Snake, after Fox shot the radome, allowing Snake to destroy REX.
A former member of FOXHOUND who we really just cannot believe anymore. First we thought he was with Liquid Snake, then we thought he was with Solidus, and now we know he's with the Patriots. Expect him back in MGS 3. His arm was removed by Grey Fox at Shadow Moses, and now carries the arm of Liquid Snake.
Liquid Snake was a member of FOXHOUND and is the identical twin of Solid Snake. His real name is unknown. Yes, this picture looks like a toy because it was the only picture I could get. He was the leader of the terroist attack on Shadow Moses island, where he hyjacked a nuclear weapon, Metal Gear REX. He was killed by FOXDIE after his failed revolution at Shadow Moses. Since then, he lives on through the right arm of Revolver Ocelot. As far as we know, he has plans to rid the Patriots but we do not know his motives for this.
The character you control in Metal Gear Solid 2: Sons of Liberty. Unlike Snake, he lacks field experience and is still very naive as a soldier. However he was once a child soldier, raised by his Godfather, George Sears, who had killed his real parents when Raiden was very young. He was also the victim of the S3 plan, to test if human behaviour could be controlled by the Patriots.