Keith is one of Jake's former squad members and a cyborg militant who committed the murders Jake was accused of. He is one of the main antagonists of the game and has a grudge against Jake for killing him prior to his becoming a cyborg. Keith is a large, broad shouldered man with a raspy voice who has a thin strip of white hair running from the front of his forehead to his neck. He also seems to have a heavily modified body in comparison to Jake's which includes a gatling gun hidden inside his arm and long, thin "wings" that extend from his back and allow some control during aerial combat but do not allow continuous flight.
Keith also has a seldom-used "Final Limiter" which changes his appearance dramatically and allows him to become stronger and faster for a seemingly unlimited amount of time. He uses this form when he fights Jake for the final time in the game. This form also allows him to maximize the use of his plasma blade and grants him the ability to use an attack which can slice a bridge in half (this happens in one of the game's cutscenes).
Keith becomes a playable character after completing Story Mode once. He can be selected by highlighting "New Game" then selecting him as the character. Keith has all the same abilities as Jake and does not obtain the bridge-slicing move during story mode at any point.