Name: John Campbell, Sgt
Age: 31 (at time of death)
Height: 5'3"
Weight: 350 lbs
Powers: A war robot
John Campbell was a soldier fighting on the front lines when he was killed by an artillery round falling next to him. The government found what was left of him and preserved a large chunk of it, rebuilding it surgically until the mind inside returned to life. The corpse, consisting of the head, torso, and part of the right arm of Campbell, was placed inside a specially made war robot and hooked up to control it.
The robot was more or less human-looking, with exposed pneumatics in the arms and legs and a face that looked like a gas mask that housed many of its sensors. The corpse, however, was entirely contained within the chest, so the head could, in theory, be removed without killing Campbell.
?By inserting his robotic arms up to the elbow into special weapons, Campbell can carry heavy weapons into combat that linked directly into his brain, allowing unheard-of control and aim. When using a heavy cannon, a special tail is added to his body to absorb the shock. Other weapons include a mingun, rail gun, grenade launcher, and flamethrower.
Because John Campbell is officially dead, and because the institution where he is held is the only place in the world capable of servicing his special robotic body, John Campbell has, effectively, become government property.
What he doesn't know, however, is that he's been told a lie. When his corpse was placed within the robotic body, the brain was entirely downloaded into the robot's computer brain. Then the corpse was removed and disposed of. The machine known as John Campbell is, in fact, totally inorganic, and merely has an imprint of what were the human John Campbell's memories.
Another thing he is unaware of is that those memories are very limited. While he remembers that he had a mother, for instance, he does not remember her name or even her face. A lot of such "unimportant" memories were removed when the government transferred the mind of the corpse into the robot. John Campbell doesn't even know that he is missing those memories, until someone asks him who his mother was.