The Kid is the protagonist of I Wanna Be The Guy.
He becomes a playable character if you are able to complete his Warp Zone. Like Ogmo, he has the ability to double jump, but has better vertical reach. He is better than Ogmo overall, but Ogmo is better if you want more of a challenge. Unlocking him will unlock the achievement "The Kid", for both the Xbox 360 (10 Gamerscore Points) and the Steam version.
The first level of his warp zone was altered and added to the "Expert Remix" chapter on Teh Internets, a chapter that consisted of previous levels, but made exceptionally hard. The only character available in this is Meat Boy.
In a poll on the Super Meat Boy forums, The Kid was voted as the most favorite guest character, obtaining just over a third (41) of the 120 votes. The Kid got over 3 times as many votes as second place Captain Viridian (12 votes).
Name: The Kid
Location: 5-7 "The Fallen"
Origin: I Wanna Be The Guy
Age: 15 (According to his game)
Pro: Double-Jump (Better than Ogmo)
Cons: Slow speed, really hard to unlock