Corporal Harold Fischer is a human crew member onboard the Firestorm.
Harold wasn't originally a spacer. He was a simple fisherman, living off the sea. Because of his profession--and his distrust of advanced equipment--he honed his sense of direction to an uncanny level. He learned how to have lucid dreams for the specific purpose of keeping track of where he was going even while he slept.
Eventually, his planet was attacked in a terrible war. Deciding that he needed to help, he enlisted with the marines. He didn't rise up the ranks quickly, he didn't have a particularly stellar career--he only made it to Corporal, after all--but he retained his gift for direction, and this is what saved him. In a battle that killed most of the rest of the crew of his ship, while he was still a lance corporal, he was able to take one of the dropships of his troop transport and bring it back into friendly space despite the navigation computer not being designed for interstellar travel.
He was given a medal for showing leadership skills and promoted to corporal. He was approached by the marines for working onboard a new ship: the Firestorm. While he yearned to go back to his boat--the war was over, it took that dropship a long time to get where it was going--the marines insisted he was still needed, and convinced him to stay on.
Harold has an uncanny sense of where he is in the universe. He is constantly aware of his body's orientation and can estimate his speed and direction simply by feel. He can find his way from point A to point B in pitch blackness.
Because of his experience with maps onboard his fishing ship, Harold takes very well to math.
Harold's marine training makes him very dangerous in a fight and he has no problems with fighting dirty if he needs to. His sense of direction and mathematical abilities can help him to predict opponent's moves.