Dr. Kerr is the associate of Konoko's father, Dr. Hasegawa. They worked together on the Syndicate's payroll because no one else would fund their work to save the world from the BioCrisis. When the Syndicate turned out to have their own plans for their research and raided the lab, Kerr fled with the three year-old Mai to the TCTF, where Mai grew up under Griffin's watchful eye to become the TCTF agent code-named Konoko. Konoko later finds out that Kerr is her mother's brother.
Besides Shinatama, Kerr is the only trustworthy character that Konoko knows. This is illustrated by cutscenes starting with Chapter 1, where he argues with Griffin out of concern for Konoko's safety, and especially in Chapter 8, where he pleads with Griffin not to try to kill Konoko with Shinatama's self-destruct signal. Although Kerr is the one responsible for implanting the prototype Chrysalis in her, Konoko realizes that he was made to do it by Griffin, and that her uncle does care for her. Kerr ends up giving his life to protect Konoko from a Mercury Bow shot in Chapter 12, shortly after telling her much of what she needs to know in the game's longest expositional scene.