Dr. Warren was one of the main antagonists in the horror series 28 Days Later as he was responsible for the creation of the Rage Virus and all its destruction. The Infected were also his creations too. Dr. Warren was unremorseful unlike his counterpart Dr. Clive, and Dr. Warren was obsessed with science and would do anything to make it work.
Seeing all the chaos and destruction the violent riots had produced round London, Dr. Warren decided to make a violence-inhibiting genome which would make people calmer. Dr. Warren mixed around with different formulae and strands and eventually found the Ebola virus which he then mixed with his inhibitor. Unfortunately the virus mutated, and produced a new virus, which made people extremely angry and aggressive. Dr. Warren tested it on a violent criminal whom he had got from a police cell, but it made the man even more violent. So Dr. Warren shot the criminal. Whereas Dr. Clive was horrified, Dr. Warren was merely disappointed.
It was revealed the doctors were hired by the Financiers, a team of wealthy businessmen who had hired the pair to make people calmer. Dr. Warren was talking business-like on the phone to one of the businessmen where Dr. Warren said Dr. Clive had killed himself due to the creation and he was disappointed in the results. The Financier said perhaps it was for the best, but then Dr. Warren heard scratching at his laboratory door and went out to check, but was Infected by a rabid monkey which vomited Infected blood in his face. Dr. Warren screamed and then became an Infected. Dr. Warren now screamed in rage and went round killing people, Infected by his own creation. He then died of starvation in two months.