Born October 18, 1921, in Konigsberg, Aldrich Emil's early life was nothing remarkable. He possessed an above average intelligence and health, and studied medicine at the Humboldt University of Berlin. In most ways, he was just an average pre-Nazi German person, and, like most pre-Nazi German people, once the goose-steppers came into power, he got swept up into it.
He joined the Nazi Party shortly before finishing his studies, and after graduation he joined the SS. At first he served as a medic in the German army, but he was transferred to concentration camp service in 1944, and worked under Mengele at Auschwitz. Most of Mengele's experiments were blatantly worthless and unscientific, but, being a German in World War 2, Aldrich did not care. He changed his tune when it became obvious that Germany was going to lose, and gathered as much useable research material as he possibly could before the Red Army liberated the camp. He hoped to avoid a trial by offering his services to the Soviets, who, eager to get their slice of the Nazi scientist pie, accepted.
Thus began Aldrich's life as a soviet researcher. The soviets were no stranger to incredibly strange experiments, so Aldrich's... talents... did not go unused. He worked primarily on the development of biological weapons, and more than one new deadly strain was due to his work. As everyone does, however, he eventually got old, but before the Soviets could thank (execute) him for his long years of service, Armageddon happened, and as far as anyone around him is concerned, Aldrich is just some old dude who knows a lot about medicine and the second world war.