Hans Klerber is a member of March 33 terrorist group and a former member of the German Special Forces. At some point after the first Gulf War, he worked with American Delta operatives John Bradley and Mick Connors on a counter-insurgency mission in Munich. At some point, he defected with several of his men to join the terrorist organization March 33 for unknown reasons and led one of their most effective cells.
He and his men were responsible for breaking out known terrorist associate Mandel from government custody in Colombia. They were caught on camera and identified by Connors and Bradley, both now part of Red Team, which was tracking Mandel. When Red Team's intelligence officer, Strachen, defected, Klerber and his men were sent to protect him. With new information, he held undercover asset Alan Connors, brother of Red Team member Mick Connors, hostage along with several civilians in order escape their base in the Philippines. He was killed in a firefight when Red Team launched a rescue/capture operation against his men, but not before killing Alan Connors.