Samantha Maxis was, reportedly, born to Ludvig Maxis and his unknown wife. After his wife died, Maxis made sure she was always close to him. Due to his research, however, he neglected her and failed to notice Richtofen's experiments on her. As the experiments went on, Richtofen discovered more about Samantha Maxis as he learned more he grew to hate her and Dr. Maxis, perhaps due to Maxis' attachment to her or due to what she and Maxis had become. When Richtofen trapped Samantha in the room with Fluffy, her dog, and activated the teleporter, she was teleported to Griffin Station. There in a panic she accidentally came in contact with the M.P.D. and took control of the zombies. In an effort to stop her and free her so that Richtofen could operate it, Groph and Schuster found and brought Maxis to her. However, Maxis told her to kill them all and was killed shortly after, sending Samantha over the edge and on a rampage to destroy all of the Group 935, which had betrayed and killed Maxis. After Richtofen trades bodies with her to control the zombies, she and the super soldier test subjects activate Maxis's backup plan and incinerate the earth, leaving Richtofen trapped in her body and able to control the zombies on the Moon and the remaining zombies on Earth.
After the events of Moon, Samantha traveled back in time through unexplained methods and found herself trapped in Agartha in 1918. Upon learning of her disappearance in the present, Dr. Maxis sought help from the Earth's survivors in opening a dimensional rift to the Aether, allowing him to overthrow Richtofen, commandeer the Aether's energy and open the gateway to Agartha to reunite himself with his daughter. After the Group 935 excavation site in Northern France was overrun with zombies, Samantha was able to convince the young Tank Dempsey, Nikolai Belinski, Takeo Masaki, and Richtofen to free her.