Robert Hunter was born in Scranton, Pennsylvania. Due to genetic alteration carried out on him by the Kree Lunatic Legion, Robert gained the ability to explode and reform himself at will. Some time later, he exposed Captain Marvel to a nerve gas, which ultimately gave him cancer. Since then he has clashed with Earth's superhumans, and been defeated by the "fractioning (separation) of his exploded mass" (essentially, if he can't reform himself after an explosion, he can't explode again). Nitro was hired as a hitman to kill Matt Murdock, but Nitro was apprehended by police.