Gears of War 3: How to Unlock Clayton Carmine
In Gears of War 3 for the Xbox 360, a lot of the unlockable characters in the game are unlocked simply by leveling up your character.
To unlock Clayton Carmine, you need to reach level 14. You gain experience for leveling up through all game modes, offline and online, so just keep playing and gaining those levels.
Check out my other guide for more unlockable characters in Gears of War 3.