You were a scientist for TF141, Gaz was a member of the task force. Due to an unfortunate mission failure where the target had created some kind of gas to turn people into zombies, Gaz had fallen victim to the effects of the gas.

You were the only scientist he even let get remotely close to him. The truly strange thing however, was the fact that he kept his consciousness and brain, but now needed human body parts to survive. Now here you both were, working on a formula to turn him back.