Stephen Krieg is a german scientist, doctor and physicist. He often likes to experiment with science and technology. He is well high in the ranks and well known for his excellent results, but others [especially former patients] constantly say hes either insane or cruel. This is most likely due to the fact that he enjoys to experiment on his nearly dying patients to see if he can do all sorts of things in the medical and mechanical department.
Not much is known about this doctor other than the fact that he enjoys alternate experiments and new ideas of medicine. However he isn't a monster, he usually heals his patients and make sure that they survive whatever thwy suffered. Some made statements that he used to work with the SCP foundation as others believe that he used to work for gentek during their prototype project, though both theories were never stated true nor false.