Nathan was born to a well off family in Miami, Florida. David Barnett, Nate's father owned a successful shipping business and ran several planes and trucks across the southern states. During his teenage years, Nate fell in with the wrong crowd. Some of his spoiled, rich prep friends introduced him to cocaine at their parties. Nate soon became an addict. A school counselor had taken a shine to Nate early on in high school. He recognized the difference in Nate's behavior. Nate realized he had a problem and kicked his addiction with the counselor's help. They never informed his family.
When Nate finished High School, he decided to enter law enforcement and join the Drug Enforcement Agency. He decided he wanted to make a difference in the war against drugs and wanted to bring the dealers and manufacturers to justice. Soon after joining the academy, he met J. Graham Prescott (Hunter) and the two became friends. They had a friendly rivalry that continued throughout their training. Prescott did better at the combat oriented training while Nate was more cunning and excelled more at operations using spy tactics or stings.
Prescott and Barnett were teamed as partners after a brief apprenticeship under some more experienced agents. They ended up with the greatest success record known in the agency. They made several high level domestic arrests and took part in foreign raids in Columbia and Panama. Unfortunately, one of the manufacturers in Panama was a front for the Secret Empire's Biological Research division. Prescott and Barnett's team was hopelessly outgunned. They lost several men while retreating and Barnett was caught in the blast of a new experimental plasma cannon. Although Barnett survived, his face was horribly scarred. Even with the newest advances in plastic surgery, doctors said he could never completely recover. During the next few months, Barnett's addiction surfaced again and in his depressed state, he couldn't resist the urges. At first, he was abused morphine due to his pain and then fell back into cocaine. During this time, Secret Empire agents were spying on Barnett and Prescott to see how much they truly suspected about their "cocaine factory" in Panama. When agents uncovered Barnett's addiction, they saw an opportunity. They came to him and said that they could repair his face if he would be a spy for their "crimeboss". Barnett accepted and underwent an experimental form of gene surgery to repair his face. Secret Empire scientists also discovered that he was an excellent candidate for their newest experiment: developing super powers in human beings. They had acquired Professor Phineus Horton's notes on the Human Torch and thought this was process could be replicated. After kidnapping Horton for hands on experience, they had him combine the Torch technology with the theories behind their new experimental plasma cannon. The result was stunning. Barnett could emit and control plasma energy. The scientists decided not to make Barnett a direct spy but rather gave a post-hypnotic suggestion to do their bidding sometime in the future.
Barnett was returned to Miami with memories of having gone to Europe for a new surgical procedure on his face. When he discovered his powers, he believed that the plasma cannon had altered his body and given him these fantastic powers.
Barnett decided to use his powers for good despite his current addiction, calling himself Chaos due to his new chaotic powers. After a few successful battles, Chaos was noticed by Raven and offered membership in a covert government organization known as The Dark Force.
Chaos was one of the most effective members of the team and helped them take down several criminal groups from Yakuza sects to the Masters of Evil. Unbeknownst to the team however, Chaos was subconsciously reporting his missions and knowledge to the Secret Empire at regular intervals. After a successful mission to Japan, Nightbreed's demonic nature became dominant and he attacked the team. After he left the scene, the scientists decided to activate the post-hypnotic suggestion and made him attack the team while they were weak. His attack caused the death of Phantasm, his teammate.
Barnett has since thrown off the Secret Empire's influence but the conditioning, addiction and his mutilation have taken their toll and left him schizophrenic. He is unstable and extremely dangerous. He is one of the Cavaliers' deadliest foes.
Chaos' powers derive from plasma energy. He can generate this power from nearly anywhere on his body. He can perform many feats with this power, including wrap a white-hot sheath around his body for protection and he can fly. He can emit a plasma bomb from his body that will cover a radius 50 yards and he can survive in a vacuum or space for several days by suspending his bodily functions and surviving off his internal energy. Chaos can also make crude shapes and can branch off his plasma stream to hit multiple targets. Chaos' control over his power is not 100%. While using his plasma, he can lose control and explode releasing a wave of energy. Chaos is immune to the plasma, but the shock can render him unconscious, or worse, comatose.