Brock
Not much is known yet about the inscrutable Brock. Not even his last name. It's probably on file somewhere at Kjelstad Advanced Industries where he is currently employed, but for all we know, he may have lied to HR when he got hired.
Brock served in the U.S. Army, but claims he was dishonorably discharged (which most people believe to be true; either that, or Brock is the worst liar ever) for striking an officer. Since then, he has found employment as a foreman at KAI.
His employer, Peter Kjelstad, also tasks Brock out to keep an eye on his naive and often erratic daughter, Marie. This suggests that either Peter Kjelstad possesses some superhuman ability to read people, or he may rank among the worst fathers ever.
Brock has the notable skills of flying several types of aircraft and get shot a lot without dying.