I have Changeling: The Lost and, obviously, I am working on a character as I read it.
Based on the preview material I read, I decided my character would be a beast. Which particular kind of beast I will decide when I reach that part of the book. What I know right now is that he was captured by one of the bone-shapers detailed in my previous post and used as a sort of hunting dog to track down, subdue, and bring back prey for his master. When he damaged his quarry's bones (teeth marks or breaks), his master beat him severely (likely with a bone club made from a femur). When he performed well and his master's mood was amiable, he was rewarded with one of the castoffs of his master's craft (bones he had shaped but did not like the end result).
He was married before ending up in Faerie, with one very young child. His wife is married now, whether to someone new or a dummy of her husband I have not decided (if someone new, it is because my character destroyed his replacement and "killed" himself for good in their eyes).
His other hook is that he saw a girl in Faerie, either during his durance or his escape, and wants to free her. He does not know her personally and she is not the only human he saw in Faerie, but for some reason she haunts his dreams and he is driven subconsciously to help her. At times he fears his hesitation spells her doom. At other times, he fears she is a trap to recover him.