In Metal Gear Solid 2: Sons of Liberty, the former child soldier who becomes Raiden’s enemy is Solidus Snake.
Solidus Snake is the third known clone of Big Boss and serves as the main antagonist of the game. Before becoming president of the United States, he was used in conflicts as a child soldier, an experience that shapes his opposition to the Patriots and his relationship with Raiden.
Solidus is distinct from Liquid Snake, who is the antagonist of the first Metal Gear Solid, and Solid Snake, who is his genetic counterpart. His identity as George Sears, the former U.S. president, is also a major plot fact, but his codename remains Solidus Snake.