Doctor George Wilhelm Krieger is a renowned scientist and creator/controller of the Trigens in the first Far Cry and the main antagonist in the first game. He is considered a very intelligent yet unethical scientist, devoted to strengthening mankind by any means. He controlled the Trigens until Doyle took over after Jack Carver killed him.

In Far Cry Instincts, Dr. Krieger is a biochemist who is trying to create a serum that will elicit the return of primal physical abilities long lost to humanity's evolutionary history.