Barnes worked for the United States government designing biological weapons and the antidotes. He fathered a son with one of his colleagues, Anne Forrester. Because she was married, the child, Ethan, was raised by her and her husband. At the age of five, Ethan developed Kurz disease, a rare and untreatable vascular condition. Barnes reached out to his contacts in the pharmaceutical industry to raise funding for a cure, but since Kurz disease is so rare and creating a cure would cost more than it could hope to repay, they turned him down. Barnes then resigned from his job at Arpax Systems, sold his house, went underground and became a developer and black market dealer of weapons of bioterrorism and chemical terrorism, working on the cure for Kurz disease on his own. While he made a profitable living developing and selling his weaponized diseases, he was never involved in actually deploying them, acting only as a salesman to anyone who could afford them, among them Reddington. As part of his experiments for the Kurz disease cure, he infected over 600 people in Atlanta, Georgia to find a person with a natural immunity. Several of his creations pushed the limits of fringe science / fringe theory.
He began using a weaponized version of Kurz disease against civilian targets to find a person with natural immunity. The attacks were also intended to create fear and force the medical community to invest money in finding a cure. After a survivor was found, he sedated her and took a bone marrow sample. He took the untested cure to his son, Ethan, but Elizabeth Keen stopped him from using it.
After arguing over the cure's safety, Keen shot him just as Barnes was about to inject his son. Red later confirmed Barnes was dead, seeing the coroner present at the crime scene.
In spite of his innocent, unassuming, quiet appearance; Barnes is in fact a cold-blooded scientist who has no remorse over what crimes he's committing.
He is willing to use people as potential or unknowing test subjects and does not care about his victims.
In addition to using people as his "test subjects", Barnes is also willing to take hostages as well as a means of a bargaining chip or just to buy him enough time to escape.
Barnes often targeted crowded areas that had numerous people such as an underground train or a courtroom. He would disguise himself as a everyday passenger or someone due for court before leaving his suitcase behind.
Once out of the area, Barnes would ensure that his victims would be unable to escape by locking a door with a zip-tie before he activated the contents of the suitcase via remote control. This would cause the biological disease stored inside the suitcase to emerge, effectively killing everyone in the room within seconds.
- Atlanta: 600
- The subway attack: 37
- The courthouse attack: 26
- Courthouse security guard