Fei is a reincarnation of a man named Lacan, who was of the city of Nisan as was his wife Elly (the details of the city are expounded upon in Elly's notes). He was primarily engaged in the study of robotics and AI. When he and his wife discovered that, due to injuries sustained during the war, Elly was unable to have children, he threw himself into a new kind of robotics that would incorporate biological components and be a more organic lifeform. Unfortunately, this would come at a time when the war went into full swing and his beloved Elly was killed. Now a broken man, Lacan threw himself into his work and was able to create Emeralda, the daughter he and Elly could never have. Unfortunately, although he was able to interact with her a bit as she began to acquire consciousness he died before he could properly activate Emeralda, and she would lie asleep for many centuries yet to come.