-Everett's memory of his past is broken into shattered fragments. There are some things of which he is certain, and other things of which he cannot be sure of. It comes with being a ghost, and his grasp on reality is often tenuous. When he does remember things with clarity, he recalls that he was once a Nuit. He worked in Sahova, with other Nuit, and he studied the art of summoning. He was very good, too, as he recalled. Not a master of his craft, certainly, but good enough to be allowed to have his own lab.
But then there are times when he remembers not being in Sahova, and the scenery is much different. Mountains, forests, and other types of terrain. Sometimes he is not a Nuit, either, and this often does not make sense to Everett, except for when he is thinking with full clarity, and then he remembers that he was also once a human. He lived in Zeltiva, and studied shielding at the University. His father was a fisherman, his mother also a student. He also sometimes recalls that he once had a wife, and owned a house in Zeltiva. Most of the time he can remember little else.
To Everett, his past is a mystery for the most part, but most of the time he isn't thinking about the past. It's just too hard to focus on, when his current reality is as confusing as it is. As time goes on, perhaps he will remember more, but as a new ghost his life is full of challenges, and remembering his past is the least of his concerns.
OOCI will develop more of Everett's life through flashbacks, as things trigger them, and as his mind becomes used to being a ghost.